First, you should be watching the conditions for 20 minutes before entering. Everyone hears this in the OW course, but few experienced divers (me included) do it religiously. You need at least 20 minutes to get a sense of whether waves are building or not, which is the only way to get a sense of what it'll be like an hour or two later when you exit.
The thing to remember about waves is that all the energy is at the top; that's why it makes sense to dive under the waves. The other thing to remember about surf entries is that the goal is to minimize your time in the surf zone. It shouldn't take more than 10 - 20 seconds to get through the surf zone.
BEFORE ENTERING: Mask around your neck, not on your face, so you don't lose it in the surf. We teach not to have a reg in your mouth; you don't really need it and I've heard of at least one diver that embolized as a result of breathing just as a wave descended. The timing would have to be about perfect for this to happen but, since you don't really need it, why take the risk? Hold a fin in each hand by something secure, like a strap. A wave can very easily rip one from your fingers if you only hold it by the blade. Make sure your BC is FULLY DEFLATED ... if you need to dive under a wave you don't want an 'inner tube' around your body. A couple of years ago a guy bullied his instructor to take him into large surf at Shaw's cove. His BC wasn't deflated, a 12-footer came along, picked him up and dumped him on his head forcefully, killing him.
ENTERING: Wait for the lull and walk quickly to chest high depth; stop shallower and the water won't support you, which makes you unstable and more likely to fall over. Be careful to judge "chest" deep at it's lowest point (just before a wave gets to you). Many people stop too soon, then find themselves unexpectedly in knee deep water with a wave heading their way. If you have trouble staying in contact with the bottom just bounce a bit.
Keep an eye on the waves at all times. If a wave is a "round one" simply bob over it. If a wave looks like a "flat one" then you need to go under it ... the backwash will make it impossible to run from all but the smallest waves. To duck under it simply go down on ONE knee (not two, don't dive under it head first); this leaves you ideally positioned to stand back up quickly and get going. Ducking under a wave is easier than you might think, because the wave actually 'sucks' you under it and spits you out the back side (also why you can't run from it). If you mis-judge the "chest high" point in the paragraph above and see a flat wave coming, you need to run at it QUICKLY before ducking under it. All the stuff I see about "bracing yourself" against a wave or 2 buddies holding onto each other for balance doesn't work; the ocean is just too powerful.
It should take you 5 - 10 seconds at most to put your fins on. That means no fiddling with buckles, straps, or adjustments. You should have your fin straps set to the proper setting before you enter ... I even duct tape mine (mostly to keep them from snagging kelp). This seems to be where new beach divers run into trouble, messing around with all the innovative snaps that the manufacturers insist on but aren't really needed. Put your fins on by having one leg for a "figure 4", using the opposite hand to QUICKLY slip it on. I like to hold my fins by the straps, with the tops facing my body, because it seems to work well with the 'figure 4.". Practice it in a pool, in chest deep water (away from the pool rail) until it becomes second nature, taking only a few seconds and without any need to look down.
Once you have your fins on, get on your back, kick hard for 15 - 20 feet, inflating your BC once you're sure you are past the surf zone.
EXITING: Pretty much the reverse of the above. I like to come to 6 - 7' of depth on scuba before ascending, just to avoid the surface swim. If you do a surface swim, it's a good idea to snorkel in because you can easily see the depth. Just as above, stop in chest-deep water, deflate your BC COMPLETELY (many people forget this, then panic because they can't touch bottom easily) and put your mask around your neck before taking off your fins. We teach folks to take their reg out of their mouth but, frankly, the benefit of being relaxed because you always KNOW you can breathe probably out-weighs the risk of embolizing should a wave break on top of you. Again, don't fiddle with buckles unless you simply can't get the darn things off. If you mis-judge the depth and get too deep either "bounce" shallower or, if you're waaaayyy too deep, put a fin at the end of each arm and use them to paddle shallower. The SOCDC teaches people to stop past the surf zone then paddle to standing depth this way which is ok, but is slower, takes more energy, and can make it look like you're signalling for help to people on the beach.
Timing waves on the way out is a bit more difficult, simply because of the lower vantage point, but the process is basically the same. Wait for a smaller wave, then use it to "push" you up towards the beach. If you have to duck under a wave while waiting for the lull, remember that it will push you shallower and you need to compensate by running back to chest depth. People sometimes do a great job ducking under a wave, forget this, then get pounded by the next big one. Don't be in a hurry to exit after you've ducked a wave or two; I've had to wait out a set of 12 before exiting. People get nervous, then "bolt" for the beach at a bad time.
Once you make a decision to exit, it's all asses and elbows; Pump your legs (high stepping) hard to get out of the last few feet of water and onto the beach. NEVER take your eyes off the surf until you are on dry land; can't tell you how many people do everything right, forget about the last 2 feet of waves, and get knocked over by a small wave that hits them in the back of knees and topples them (like your friends used to do to you in high school). Some people prefer to exit sideways, bouncing out, but I find it better to run forward looking sideways at the water.
If all else fails and you DO get knocked down, stay calm and crawl like a baby on all 4's; safety, not style, matters. Also try to remember that waves last only a few seconds and that even the most pathetic person can hold their breath for a minute. Finally, write your name and number on your gear; the ocean giveth and the ocean taketh, especially if you are a beach diver!
You'll hear instructors teaching students to back out of waves with their fins on .... Rodale's sometimes runs an article that teaches this ... but ignore them. It makes you much slower and less steady in the surf zone, where you need to be fast and solid. I think that's why the article is accompanied by photos of people exiting from a lake with no waves. We often see entire classes, including the instructor, get knocked down by a 2'wave using this technique.
