Everything all the racers have said some are bit contradictory playing around with water bottle upfront...

One thing others forgot to mention. Braking, don't clamp down hard cause someone is always going to be riding on your wheel. If you do have to brake, feather the brakes and go easy.

On the tight turns lean your bike, put pressure on inside hand and press down on outside foot. And try not to lean too much of your body into the turns. Expect someone to jump coming out of a turn. Expect someone to jump on a climb or at the top of the climb.

Oh stay in your drops unless you want to lock up your handle bar with someone else and crash.

tuck behind a big strong rider and make your ride easier.

If you get a flat, sit-up, don't slam on your brakes. slow down gently and let everyone pass you.

Go to a pre-race meeting and make sure you understand the rules. Especially true with crits. check in, staging area, start area, free lap? any preems etc. It may seem like a lot to remember but it really isn't.

Lastly are you attached?

And most importantly have lots of fun.