Low pressure in the front tire, around 80 psi. You can catch a rear slide pretty easy, front slide is almost always a guaranteed crash.

Do not use the brakes at all in the corners, you will go down. Brake before the corner while yopu are straight up and down but don't overdo it, you can actually go pretty fast in wet corners. Just make your turn in is smooth and try to avoid going to the inside of the corner too early, you will have to go wide on the exit, panic and brake, or stand up the bike and run off the course.

Try to make sure there is no one on the inside of you going around a corner. I've crashed twice from guys on the inside of me going down and sliding into me and taking me down.

As some one else said, stay in the saddle on the exit and pedal sitting down until you are straight up and down before you get out of the saddle.

When going over really slippery stuff in corners, like broad white painted lines, or brick or concrete crosswalks in the corners, do your turn in steps, so that as you are crossing the slippery area, you are always picking the bike up. This means you will have to lean hard before the slippery stuff, stand the bike up in the slippery stuff and "float" over it, then lean the bike down hard again after you get past the slippery stuff.