1. Learn to swim. Whitewater kayaking requires that you be a competent swimmer since the ability to handle yourself calmly and capably in and under water is instrumental in self-rescue.
2. Do not boat alone. Paddling solo affords no margin for error. At least one other person provides some kind of back up in case of emergency. Six paddlers is commonly considered an optimal group size.
3. Wear a decent PFD (personal flotation device). Yellow or orange are best for visibility both on/in the water and on land. A PFD with reflective tape or piping is even better. Avoid dark colours and anything red if you can (7-10% of men are red-green colour blind). For kayaking, don’t get a PFD that sits lower than your hip bone or it’ll ride up around your head with a sprayskirt on. Keep in mind that low-cut ‘rodeo style’ life vests are fashionable and provide good range of motion but at the expense of buoyancy. Treat your PFD with respect, not as a cushion, pillow, pool toy, or makeshift roof rack. The foam and fabric degrades over time so replace it at the first sign of wear as this is one item you do not want to skimp on (a hundred dollars every few years is a small price to pay for something you entrust with your life). Note that the floatation in ‘rib’ style PFDs degrades faster than ‘slab’ style PFDs. Don’t get a rescue vest with an integrated tow harness unless you are trained, practised, and comfortable with towing boats and doing tethered rescues. Avoid PFDs with long or loose straps, buckles, or cords that can easily snag on things. Make sure your PFD has an external attachment point for a river knife.
4. Wear a decent helmet.  Sadly, most helmets produced for this sport are utter crap. Get one that offers as much protection as possible for your forehead, temples, and back of the head. Consider getting one with a rigid brim - not so much to shade your eyes from the sun but to protect your nose and brow in case of face plants, rock scrapes, and errant paddles. Sweet and WRSI helmets seem to be most recommended by experienced creekboaters and I have a lot of respect for their opinion. A detachable face guard or full face helmet are good ideas if you do any creeking but realize that they muffle your voice significantly and make it difficult to use a whistle.
5. Know your ability. In order to paddle within your ability you must brutally assess your skill level. Paddling skill develops gradually so attempting to advance too quickly will compromise your safety. Coaching is instrumental in any sport so take courses regularly to improve your technique. Constantly practice eddy turns and ferries on easier rivers to improve your boat control. Realize that to paddle well you must paddle often - no book or DVD can replace time in your boat. Kayaking (including scouting and portaging) is a physically demanding activity so consider pursuing at least one other endurance and strength enhancing sport or exercise for conditioning. Ensure others are aware of any health limitation or medical condition you have that might compromise your safety or ability to perform or assist a rescue. Mind your medication since there are no riverside pharmacies. Abstain from using recreational drugs (including alcohol) that impair reflexes or judgement before paddling.
6. Know and maintain your equipment. Inspect your gear and ensure it's in good repair before you leave home. If you own your own boat then there’s no excuse for it not to be properly outfitted. In the case of rental kayaks, expect some temporary customization will be required for a proper fit so have removable hip pads, spare foam, and duct tape on hand. Maintain a clean profile – no unsecured items in your boat and no long, loose ropes or straps dangling from your clothing or PFD. Don’t overload your boat since the handling of a kayak is easily impaired when improperly or excessively loaded. Use the right tool for the job - get a boat appropriate to the kind of paddling you do (i.e. don't take a playboat on a steep creek).
7. Know the route/river. If you haven't paddled a particular river before but you are going with someone who has, at least familiarize yourself with the map and guidebook beforehand and bring them with you. Go on-line and learn as much as you can about the route beforehand so you know what to expect. Logs and landslips can add new hazards to familiar rivers. Do what you can to minimize surprises.  
8. Plan the trip. Trade cell phone numbers before you leave. Ensure everyone knows who all is paddling, where and when to meet, the put-in/take-out/camping locations, when you expect to return, evacuation route (nearest road/rail access, cut line, quad trail, etc), and the location of all vehicle keys and group equipment (spare paddle, rescue kit, first aid kit, medication, toilet paper, etc). Always have emergency contacts for individuals as well as the group (i.e. someone who knows where you went and when to expect you back). Agree on who will lead, who will sweep, and establish a rescue protocol before you get on the water. This is often overlooked on trips with frequent or experienced paddling partners and can lead to confusion and hesitation during an emergency.  
9. Be aware of the hazards:
   • Weather. Check the forecast before you go for the expected wind speed, precipitation, and air temperature. Hypothermia caused by cold weather or cold water immersion is probably the greatest danger you face. Wind and current suck the heat out of you incredibly fast. Realize that the weather can change very quickly in the mountains and foothills and that it can snow any month of the year. Be wary of lakes and valleys known to be wind funnels.
   • Difficulty. Class of rapids, nature of the river (canyon vs. open riverbed), size of lakes, length of portages and open water traverses, daily distance to paddle.
   • Water conditions. High water makes paddling and rescue more difficult - check river levels on-line before you go. Check maritime weather forecast for size of waves and ocean swell. Consult tide tables and navigation charts for ocean currents. If river is dam controlled then confirm release schedule. Realize that glacier fed rivers and lakes are crazy cold. During summer, glacial rivers can easily double or triple in volume by mid-afternoon.
   • Strainers. Brush, trees, logjams, undercut rocks – anything that allows water through but traps a boat or swimmer  is a strainer. Rescue is often extremely difficult. 
   • Hydraulics. When water flows over a dam, weir, ledge, or large rock it curls back on itself. This upstream recirculation can trap boats and swimmers. Lowhead dams and weirs are the worst because the uniform recirculation has no breaks through which a paddler can escape and the sides are typically sheer concrete walls.  
   • Waterfalls. These appear upstream as horizon lines as if the river simply disappears. Waterfalls are surprisingly quiet upstream. Get to shore immediately and scout. Some kayakers run waterfalls but the risks are many: becoming vertically pinned by rocks at the bottom, getting stuck behind the waterfall, getting stuck in the recirculation below the waterfall, hitting your face with your paddle on impact, landing flat and breaking your back, hitting rocks and breaking ankles, breaking paddle or boat on impact, etc. 
   • Anything hard. In addition to rocks of all kinds, avoid man-made obstacles like bridge pilings, old weirs, mill sites, any kind of water intake or outflow. Man-made structures alter the natural flow of the river making it harder to read the water. Be alert for sharp rocks caused by blasting as well as concrete, rebar, rock fill, and other debris dumped in the river. If you hit a rock (or any other solid object) lean aggressively toward it so the current doesn’t pile up on the upstream edge of your boat and flip it. Then push your boat around one side of the obstacle while keeping the upstream edge of your boat out of the current. 
   • Anything moving. Always give way to the boat downstream. However, checking for oncoming traffic before peeling out of an eddy or onto a surf wave is customary, polite, and a smart thing to do. Understand that rafts don’t have brakes, are usually full of first time paddlers, and have one over-tasked guide with poor forward visibility. Be careful paddling on lakes used by motorboats, waterskiers, and jetskis because they don’t always see or respect smaller craft.
   • Foot entrapment. Do not stand up in water above your shins - ever! Foot entrapments are very common, very painful, difficult to escape even with help, and near impossible to escape on your own. Rivers with a history of log drives are bad for this type of hazard since their bottoms are often carpeted with slippery sunken logs.
10. Use your own (and your best) judgment. Respect the directions and advice of the trip leader and other competent paddlers since it is hard to gauge the risks of rapids and rivers when you're first starting out. However, you are ultimately responsible for your own actions so strive to only make good decisions. Always assess risk yourself (probability of error coupled with direness of the most likely consequences) since you know your skill level best. You must deal with the consequences of your actions so never do anything that makes you uncomfortable. Don’t let overconfidence, excessive enthusiasm, or groundless optimism cloud your judgment. Remember:
    • You are responsible for your equipment. Select gear appropriate to your needs and ability.
    • The decision to participate in a trip is yours – as is the choice to continue a trip. You can opt out initially, at the put-in, or even walk out midway (well, usually).
    • The decision to scout, portage, or run a rapid is your prerogative. Resist pressure from others if you feel something is beyond your skill. Do not be deceived by watching experienced paddlers since they often make hard moves look easy. Also, experienced paddlers often unintentionally underestimate the difficulty of a rapid because they are judging it based on their own ability. 
    • Voice any concerns about yourself, the group, the river, the rapid, or the plan to the trip leader immediately.
    • 'Hope' is not a strategy. If you aren't confident you can make the line through a rapid and there are consequences to a mistake, then portage it instead. 
    • Don’t rely on a safety net. Safety isn’t always effective - throwbags often miss, safety boaters can be preoccupied or poorly placed, etc. As a respected western creekboater once advised: "Think of safety as being in your boat, upright, on your line, and in control."  
11. Be proficient at self-rescue. The best rescue is a self-rescue. Develop a bomb-proof Eskimo roll on both sides since it is by far the most frequent and fundamental self-rescue technique. In a safe environment, practice freeing your boat from rocks/pins/strainers and swimming a capsized boat to shore by yourself. Become proficient at surfing and escaping friendly holes so you have a clue what to do when you end up in an unfriendly one. Periodically practice the 'whitewater swimming' position and know the conditions when you should swim aggressively or defensively. 
12. Hone your rescue skills.  Start by taking a swift water course so that at the very least you don't make a bad situation worse. Effective rescue skills can only be learned through training and only remain keen through practice. Learn the appropriate knots for specific situations. Practice lobbing your throw bag and setting up a Z-drag when you're waiting for a shuttle or sitting around camp.
13. Learn First Aid and CPR. Not knowing First Aid/CPR is the same as not knowing how to roll a kayak: you are a liability on the river until you are proficient at both. Like the eskimo roll, you can't learn First Aid/CPR from a book or the internet so take a course! Also, learn to recognize signs of hypothermia (uncontrolled shaking, numbness, loss of coordination, slurred/difficult speech) since this is probably the most common affliction on the river. A wilderness First Aid course is an excellent follow up to standard and emergency First Aid training.
14. Carry emergency equipment and learn how to use it. Get in the habit of carrying/wearing all your gear all the time or you risk not having it when you need it. 
    • Throw bag. 20m (70 feet) of 3/8” polypropylene or spectra rope is ideal since it’s hard to lob a throw bag any further than about 50 feet.  Keep it ‘clean’ – no knots, loops, or carabiners at the end of the rope since these tend to snag if you have to let go in a hurry. Use it only to rescue swimmers (not to hang tarps or dry clothes). Dry and repack your throw bag after every trip so it lasts and works. Accidents happen fast so make a habit of always carrying your throw bag whenever you are out of your boat. Leaving your throw bag in your boat effectively relegates you to the role of spectator. Store your throwbag in an easily accessible spot - in most kayaks that means in the cranny with the bungie cord in front of your seat that the manufacturer pretends is for water bottles (your water will fit well enough behind the seat). Lastly, regularly practice stuffing and tossing your throwbag since there is no opportunity for a test throw in an emergency situation.
    • Whistle. Get the plastic, pealess variety and ensure it's big enough to handle when wearing mitts or gloves. Attach it to a short elastic lanyard on the outside of your life jacket. Ensure it is easily accessible both when you’re in your boat and when you're in the water.
    • River knife. Attach this to the outside of your FPD for easy access. In an emergency, you need to rely on it having a sharp edge so don't use your river knife for whittling, cutting kindling, cooking, or spreading peanut butter on your lunch. River knives are useful in case you get entangled in a rope so opt for one with a serrated edge and wire/rope cutter. They are also frequently used in emergencies to cut the PFD and drytop off an unconscious victim in order to perform CPR. Visibilty is another reason for carrying it on the outside of your PFD - that way you don't have to gamble on your rescuer carrying a knife if you're the one needing CPR.
    • Spare paddle. You will break or lose your paddle... eventually. The only way to ensure someone in your group carries a spare paddle is for that someone to be you. Get a 4 piece breakdown paddle and store it permanently in the stern of your boat. Be sure it's secured in the boat or put it inside a dry bag. If you can't fit a spare paddle in your playboat, consider hand paddles instead since they can sometimes serve well in an emergency depending on the nature, difficulty, and temperature of the river.  
    • First Aid Kit. A waterproof, wide top Nalgene bottle with a carabiner through the lid loop clips nicely into any boat. The usual stock of bandaids, gauze, drugs, and anti-septic ointments are useful but minor cuts, scrapes, and blisters rarely prevent someone from paddling. Kayakers are, however, prone to shoulder dislocation, broken ribs, and nasty head wounds so make sure your kit includes medical tape, triangle bandages, and something like a military field dressing that can soak up an awful lot of blood. If you ever paddle anywhere exotic then keep some Imodium and toilet paper in your boat as well (trust me on this!).
    • Flotation. Air bags make it significantly easier to see, tow, and empty a capsized boat. An empty boat with flotation is also less prone to broaching on rocks. Sometimes you can remain in and continue paddling a swamped boat provided it has flotation.
    • Rescue Kit. A bag containing slings, pulleys, carabiners, and prusik loops (2 of each). This is used to create a Z-drag to pull pinned boats off rocks. Consider including a length of extra rope since a 70 foot throwbag is rarely long enough. One rescue kit is rarely enough to effect a successful rescue – you'll often need to combine the group's resources. If you are paddling on rivers that may have strainers or logs that need to be cleared then consider carrying a portable/collapsible saw as well. Some creekboaters prefer to carry equipment for a minimal Z-drag (some carabiners, a couple prusik loops, and a sling) in the front pocket of their life jacket for quick access.
    • Emergency kit. This is primarily for the rare but inevitable occasion when you are stuck somewhere due to weather/water conditions, injury, or equipment loss/failure. If you are forced to hike out, wait overnight, or signal for help then you will need: a compass, a good lighter, headlamp, signal mirror, hard candies/energy bars, duct tape, emergency blanket, and extra clothing (neoprene cap and mitts). Carry a cell phone or SPOT emergency locator beacon if you have one. An emergency locator beacon is essential if you are paddling on an extremely remote or dangerous river, bushwhacking extensively, or on a multi-day expedition. If you've ever had to use one then you'll know that emergency blankets tend to be on the small side so either carry two or opt for the extra large size. Also, get a reliable, windproof, waterproof lighter - not the cheap, disposable, Bic variety.
15. Wear proper clothing. This includes proper footwear – something that you can portage or hike in. Even if you don't expect to swim, you must still be capable of performing a rescue. That is, you have to be willing and able to jump in the river at any moment without hesitation. Under-dressing on glacial or mountain rivers means that you are useless or, worse, a possible liability in a rescue situation. Therefore, a wetsuit, drysuit, or neoprene pants and a drytop are mandatory. Be mindful of pogies for keeping your hands warm - if you lose your paddle you lose your sole means of warmth.
16. Always carry food and water. Dehydration is a surprisingly common condition among paddlers since you rarely feel thirsty when you’re soaking wet. However, paddling quickly depletes your body of fluid and energy. Regardless of the length of the trip and whether you actually feel hungry or thirsty, get in the habit of forcing yourself to take frequent breaks to eat and drink when you’re on the water as well as at both the put-in and take-out. 
17. Always use sunscreen. Ensure it's the waterproof variety and at least SPF 30 or you’ll have a chinstrap tan come September. Don't wait till you're already burned: get in the habit of lathering it on before you get on the river, regardless of the weather. Don't use any gel or alcohol-based suncreen since it degrades latex gaskets on dry tops.
18. Communicate. All paddlers should maintain line of sight with each other whenever possible. Always ensure someone knows where you are if you need to leave the group to pee, take pictures, empty your boat, adjust your outfitting, etc. Establish whistle, paddle, and hand signals at the start of the trip - especially important when paddling with someone for the first time. Debrief the group after any rescue, emergency, or close call - remember that you can learn as much from a rescue done right as a rescue done wrong.
19. Anticipate problems. Accidents happen fast - so fast that people can't react quickly enough to avoid them. Watch some of the kayak carnage videos on YouTube and you'll see that things typically go from perfectly fine to complete disaster in 3 seconds or less. Therefore, you need to position yourself properly from the start to be of help. Try to anticipate where someone might get in trouble and site safety boaters and throw bags where they are most effective (which isn't always closest to the danger). Recognize when a situation is about to turn bad and react quickly before it gets truly out of hand (i.e. start your rescue when someone misses their roll - don't wait till they are impaled in the logjam just downstream). Think and act fast the instant you see something start to go wrong. 
20. Have the right attitude. Enthusiasm is one thing, but a cavalier "just give 'er!" attitude to kayaking is immature and dangerous. Swimming is not the worst thing that can happen in this sport. Serious accidents are rare, but the risks are real. Don't think that you're special, gifted, lucky, talented or somehow immune just because you've never been lost, injured, broken gear, had a nasty swim, or a near-death experience. The reality is simply that it hasn't happened *yet*.

References