How do you avoid and recover from broaches?
A boat is most vulnerable broaching (or jibe broaching) when the rig is loaded up. This usually happens at the bottom of a wave, where the bow digs into the next wave, slowing the boat and the rig tries to keep on going. Ideally the helmsman wants to go dead down the wave and then head up a little in the trough to avoid this.
Remember that steering corrections on a run should be as small as possible. The worst thing you can do when you start to round up is overreact. An inexperienced helmsman will typically crank the helm over as the boat starts to luff up, but when the sails fill and flow attaches to the rudder, the boat will have so much momentum going the other direction that it will do a jibe broach. The important thing is to try to get flow on the rudder without making too abrupt a movement. Keep ventilating the rudder (by giving the helm quick tugs) to get rid of a stalled bubble, and work the boat do to the compass course that you were originally on , or maybe a little lower. If feel like the boat is about to round up it's probably better to call for a spinnaker luff and keep the boat going straight than it is to broach. At least that way you won't lose all your moment down the course. If you do broach, the first sail that you trim back in should probably be your spinnaker. Just as you depowered the boat from back to front, you should power up from the front to the back.

What can you do to help the boat surf in waves?
One of the best downwind drivers I've ever sailed with is Mark Soverel. He's unbelievable and it's because he's a surfer [Ed's note: Soverel died in January, 2002]. Steering a big boat down waves is no different than surfing. What you're trying to do build up boatspeed and apparent windspeed by steering across the wave. You then use this speed to make optimum VMG to leeward by turning (maybe 10 to 20 degrees) and going down the face of the wave. When your bow is about to dig into the next wave, head up so that the rig doesn't become overloaded. It's definitely not fast to go in a straight line. My advice is to watch a surfing contest on television, and just study those guys go across waves.
In surfing conditions, the helmsman should look for troughs on the windward side of the boat and also watch the bow wave. If you see the bow wave starting to get bigger, then it's time to head up little. You want to pick the biggest wave to surf on, and this is where looking behind, or having your tactician look behind can really help. Every third wave or so is bigger than the others. Spend most of your time going down the big wave rather than trying to go down the little waves and missing the big ones. You have to discriminate. Steering by the lee can be very fast when you're on a wave. Another trick that some helmsmen use for catching waves is wriggling the tiller just as a wave starts to lift their stern. I think this breaks up the suction that's created when a boat is moving through the water and stops the boat from being sucked into the wave. It's like breaking up the ground effect on a race car.

What's the fastest way to steer during a jibe?
You lose very little by jibing downwind as long as your crew can execute a jibe properly. So one basic rule of thumb is that the helmsman ought to jibe at a speed that's good for the crew. It's no good to spin a fast jibe if the spinnaker ends up inside the headstay. Ideally, though, if you jibe only for the benefit of the crew, you'll usually be steering through the jibe too slowly. They problem with turning slowly is that you don't have apparent wind building fast enough on the new jibe. As a result, your speed stays in the low range, and it may take a long time to get it back up again. You should almost always turn more sharply than what you think would be right in a jibe.
By and large, you want to come out of the jibe a little higher than the angle that gives your optimum VMG. Your goal is to load the boat up (with apparent wind) on the new jibe as quickly as possible, because when you jibe you are making great VMG for a while (since you're headed straight downwind), but you start losing all your apparent wind. If you don't come up fairly sharply just after the jibe, you'll lose too much momentum Your course should be up and then down-that's the ideal jibe. The only exception to this is when you're sailing downwind in a lot of breeze and you don't need to sail higher to get back up to speed

Where are you looking as you jibe?
I watch the spinnaker the whole time. The reason for this is that the helmsman should call when the pole is tripped. You ought to yell "Trip" when the pole is fully squared (i.e. the boat is headed dead downwind or slightly by the lee), and this is the moment when you want to start turning the boat a little faster.

I use the angle of the Windex and the compass during the second half of the turn to help me know what heading I should be on for the new jibe. I try to end up so the Windex is a little farther forward on the new jibe than it was on the old to keep speed up. Another rule of thumb on a run is that if I'm sailing with the Windex about 25 degrees forward of dead aft, then we'll jibe through about 25 degrees. In this case, I'll say, "Let's jibe through 35 degrees, keep good speed and then bear down to our optimum angle." As we come out of the jibe, I'm looking for a rough compass course and Windex angle.

It's safe to say that helmsmanship does not win races by itself, but it can certainly make a big difference. Both upwind and downwind, the best drivers can sense how a boat is going by the feel of the wheel or tiller, and they are quarterbacking the whole team according to this. Practice using all your senses when you're steering, and don't get hung up on any one aid like instruments or telltales. Communicate with your tactician and trimmers, and keep the boat sailing on the fast side.