Read Freedom of the Hills. If you already know how to trad climb, practice
- prusiking up. This is probably the only thing you will ever use in an actual crevasse fall
- snow anchors
- imitation of the following scenario (with two people), which includes everything you might need to do in the worst possible situation. Everything else is a subset of this.
You're walking around on a shortened rope with kiwi coils and knots along the rope connecting you to your partner. Someone falls into the crevasse. Self-arrest, make a bollard, deadman, or bang in a couple pickets, make anchor, transfer tension onto anchor, you are now free to do stuff. Take coils off, use coils to rap down to partner (after checking to see if it's necessary--i.e., if he needs immediate medical attention), help partner, prusik out, create 6:1 pulley system, haul him out. It takes practice to get the details ironed out, especially if you're not using convenience gear like traxion pulleys. Places where stuff can go slowly or wrong: getting him over the lip (prepare it), not having enough rope for the intended tasks, anchor being shitty (use a deadman). Remember, forces on the anchor will be multiplied, but it's not a huge deal because of snow-rope friction.
In the following excerpt, I described to a friend how we practiced this scenario on a college campus. It involved some "bungee" jumping off the roof of the dining hall, which was fun and probably decreased the lifetime of the rope involved.
What we did was: a group of two would tie in as if simuling with a shortened rope or glacier walking (kiwi coils on both climbers and tied into the ends of the rope), one would "jump" into the "crevasse" (walk off a roof to a courtyard), the guy on top would make an anchor (figure eight on big bight looped around a chimney instead of deadman/pickets), transfer tension onto the anchor, untie, prepare "lip" (pack over edge of roof), rappel down, attend to fallen climber (take pack off, etc), attach pulley to fallen climber, prusik back out, set up a 6:1 hauling system, haul fallen climber up. After practicing ascending, knots, and kiwi coils separately, people took about 1.5 hr to work through that process the first time and considerably less the second.