Yes you first time you get on stage you're going to be scared out of your wits.

DON'T have a drink to "calm your nerves". It is very habit forming- I've worked with girls who can't start the night without a few shots of "liquid courage". Drinking on the job is a really bad idea; it can let you permit guys to take liberties you would not otherwise allow - including getting in their car after work. If a guy offers to buy you a drink ask for a Diet Coke or juice.

Entertainers