Do you think you're the only scuba screw-up on the boat? That you're the only one who gets lost and misses the best action, or blows off all his air early and has to wait on the boat like a naughty kid in after-school detention? You think you're the only one whose mask strap goes ping! as he's blocking the entry doorway of the Spectre off Santa Cruz Island?

Been there, done all of that, learned the lessons the hard way. My editor says my loss is your gain, that you're going to learn from my biggest mistakes. I think he just wants a good laugh at my expense, but in any case, here are six things I've learned the hard way:

1) Anxiety Floats

It was one of those wild drift dives in Cozumel where you skim the ground like a Tomahawk missile, but I was having trouble with my altitude control circuitry--always too high off the bottom or too low. I kept fiddling with my BC controls and pretty soon the divemaster was at my elbow, giving me the fisheye.

What I learned (and I'm not telling how many years it took) was the importance of a proper buoyancy check at the start of a dive trip. Sure, I had gone in the water at the dock and piled on lead until I could submerge, added air to my BC until I was neutral and bingo, my buoyancy check was done, right?

Wrong. Like most divers at the start of a dive trip, I was carrying extra weight, which required extra inflation of my BC to float it. That extra-big air bubble inside my BC destabilized my buoyancy because it expanded and shrank every time I rose and descended.

Why was I overweighted? The same reason most divers are overweighted after the off-season--nerves. When you're anxious or excited, you tend to keep your lungs more than half-full and you tend to fin a little when you think you're just resting at the surface. All that keyed-up behavior creates lift, which dupes you into adding weight.

I've learned a few tricks for making that buoyancy check count. First, I spend extra time getting the last bit of air out of my BC. I roll to the right to get any bubbles under the exhaust valve on my left shoulder, then I hold the valve open until all the air is out. Often, there's a stubborn bubble left in my BC behind my neck. Leaning backward as if in a recliner chair helps move the bubble forward, making it easier to let out.

When I want to sink, I concentrate on going limp, so no part of my body is moving. One trick is to tuck my fins under my butt and grab my ankles. That immobilizes hands and feet.

Next, I exhale completely and hold it. If I sink gently, or at least get my nose under water, I'm almost there. I add weight until I do, but if getting under the surface is too easy, I take off a pound or two. All that's remaining is to add five pounds to compensate for the weight of the air I'm going to use up during the dive, and I'm usually spot on.

2) Don't Play Follow the Leader

"Wow! Did you see that eagle ray?"

Uh, no. Fact is, I was following the crowd, which was following the leader, and we all missed it. Call it timidity or habit or laziness, but "follow the leader" is the norm at most dive resorts, and I was normal for far too long.

But I've learned, finally, how to venture off into the great unknown and not get lost. How do Lewis-and-Clark types like me know where we are and find the boat again? I use the natural clues to direction and a little instrumentation, but most of all I've learned to keep the "big picture" clearly in mind. I visualize the whole dive area with the boat and the reef located in it. I include the direction of north in case I have to use my compass, and the "fall line." That's the route a falling rock would take tumbling down the slope of the bottom. Deeper or shallower is one of your best orientation clues. As I dive, I constantly update the picture and my location--moving the diver icon across the screen, so to speak. If in doubt, I sketch the site on my slate, but usually I don't need to look at it again because just drawing the site clarifies the picture for me.

Once under water, I've learned to break my route into short here-to-there legs. Before I swim from "here," I look ahead to "there" for some kind of landmark no farther than the edge of visibility. It might be an unusual rock or sponge on the edge of the reef. When I get "there," I look back toward "here" to see what that leg will look like on my return trip. Then I look ahead for the next landmark and notice if my route is curving left or right. All the while, I keep in mind my sketch of the whole site and where the boat and I are on it.

3) Love Doesn't Have to Hurt

Here's a good one: for years, I traumatized my middle ears at the start of every dive trip. I descended, my ears hurt, but I kept descending until something went pop and the pain suddenly went away. I couldn't hear too well for a week or so afterwards, but I thought that was just a normal part of diving.

Wrong again. I was actually giving myself "middle-ear barotrauma," which is a medical term for being as dumb as a box of rocks. Specifically, I was rupturing the delicate membranes between my eardrums and my inner ear structures. The pain was my eardrums screaming. The temporary deafness resulted because the space behind them had filled with mucus and blood instead of air. I could have permanently lost some or all of my hearing if infection set in. If I had hammered my inner ears, I could have experienced sudden vertigo. But I was lucky. I can still hear OK, and if I someday go deaf I'm blaming those Led Zeppelin concerts, not my feeble attempts at "equalizing."

Yes, I knew about the Valsalva maneuver--holding your nose and blowing gently--but it rarely worked for me. Since then, I've learned to equalize early and often. All I have to do is swallow, or maybe hold my nose and swallow. If I hear a "pop" in each ear I know I'm equalizing, because that's the sound of a little air hitting the insides of my eardrums.

If you don't hear the pops, you can't dive because it means your Eustachian tubes are blocked, maybe by mucus. The last thing before submerging, I equalize again to "pre-pressurize" my ears and get a little ahead of the game.

That's the "early" part of ear equalizing. "Often" means just that. I equalize as soon as my head is under water, and again every few feet of descent to 30 feet or so, when I can equalize less often. The main thing is to equalize before you feel pain or pressure in your ears. The longer you wait, the harder it is to do because your Eustachian tubes actually have one-way valves at the throat end that close under pressure.

And don't try to blow the top of your head off. Blowing too forcefully can hurt your inner ears. I blow gently, and if I can't hear the pop, I ascend and try to equalize again. I keep ascending and trying until I succeed, then I can descend again. After I reach the bottom, I equalize again even if I don't feel the need because a pressure differential too small to feel can gradually cause barotrauma in 30 minutes or so.

4) Take It Easy, Use Less Air

In diving, the great mark of shame seems to be using more air than the next guy. I actually escaped this particular embarrassment because in my formative years I dived in cold water with a wetsuit that couldn't cut it, so I was only too happy to get out of the water early (more on that later). By the time I could afford to travel to warm water, I was a pretty relaxed diver, and relaxing is the name of the air-conservation game. Less energy used is less air used.

That, and taking slow deep breaths so you get the most gas exchange, the most benefit out of the air. Shallow breaths mostly stay in your throat instead of your lungs. I learned a good air conservation trick from the late Jon Hardy: pause before exhaling. Inhale deeply and hold it a couple of extra seconds to get the most out of it. Hold your breath with your diaphragm, not by closing your throat, so there's no risk of embolism if you ascend at the same time. (And no, this isn't "skip breathing" if you keep your airway open and the pause is short.)

5) Happiness Is a Warm Diver

Remember that wetsuit that couldn't do the job? I sure do. It was a good one for the time, 7mm and custom-made to measure, so if I was cold by the end of the dive I assumed it was just another "get used to it" situation.

Wrong again. (Is there a pattern here?) I was chilled because I left my head exposed and my collar slightly open. My open collar scooped up cold water as I swam forward, and that cold water forced itself down my torso and legs and finally out the ankles, taking my body heat with it like a burglar running down the hall and out the bedroom window with the wedding silver.

But even when I'd figured out the hood and collar thing, I was still getting cold, even when I was diving in warmer water, and opting out of the third dive of the day. The reason, I finally learned, is that the custom-made wetsuit I liked so much was simply worn out. It looked fine, but a lot of the cells inside the neoprene had collapsed, thus losing their insulation value. My wetsuit may as well have been a cotton sweat suit.

I had hastened the collapse of those cells by crunching the suit into dive bags and by dumping weights and other heavy stuff on top of it.

The lesson is to wear a hood and buy a wetsuit that fits so no water flows through it, robbing you of warmth. Treat your neoprene gently by using those hangers with fat round shoulders or by folding it loosely. And be prepared to trade it in every hundred dives or so--more often if the dives are deep.

6) It's My Life

I take my life in my hands these days, because that's where it belongs--not in yours, my buddy's or the divemaster's. Here's how I learned to make my own dive decisions:

Ralph and I went out on another diver's small powerboat. Our host insisted we all dive a deep pinnacle he'd discovered. "We're anchored on it now, follow me!" We did, though neither of us wanted to. The dive was deep, dark, murky and cold. The pinnacle, when it appeared out of the gloom about a foot from our masks, looked as interesting as a concrete bridge abutment on a foggy night. Ralph and I circled it once to say we'd done it, then surfaced. And here's the odd thing: As I circled the pinnacle, I held the reg in my mouth with my hand as if it might jump out.

What I had experienced without recognizing it was a form of nitrogen narcosis. Divers usually associate narcosis with euphoria, but in fact, it amplifies whatever mental state you're in. I was feeling anxious because I didn't want to be on that deep pinnacle, but I was too much of a wimp to "wimp out." I finished the dive unhurt because nothing challenged me in my narced condition, but I learned then that when a voice inside says "Don't," it means: Don't.

Another dive, another ocean, years later. We were well into a week of repetitive diving and well into the dive when someone spotted an arch below us. Down he went, deeper and deeper, the rest of the group following like ducklings. It looked like fun, but the voice inside said "Don't."

I watched the divers getting smaller and smaller below me, then kicking hard to get through the arch and up again. That afternoon I saw a lot of nervous comparing of computers, and I saw one diver sucking on an oxygen bottle, his eyes big and round. No one admitted to signs of DCS, but no one raved about how cool that arch was, either. I didn't regret my decision one second. I hope theirs was a "pinnacle dive" like mine, a learning experience.

I could go on and on, but don't make me. Surely you've profited enough from my screw-ups, and had enough laughs along the way, too.