Know your music. - Make sure you have your music almost memorized.
This way you can be confident that you will be able to play it perfectly.
Don't worry about messing up. - Don't worry so much. Don't
go into the audition room saying "I am doing this to win," Instead
go into the audition room saying "I am doing this for fun." Music is
not about who is better, or who will you beat, but about having fun.
Don't focus on one thing in the audience. - One thing musicians
will do is focus on one thing in the audience. This works well until
that thing moves or gets blocked by something. When you do this you
are focusing on that one thing and when something happens to it you
lose focus and concentration and mess up.
Don't eat or drink anything with sugar or caffeine before you
play. - When you eat sugar or caffeine it makes your body jumpy
and unstable, this extra energy will drop quickly and if it is during
your audition then you may have a problem.
Make sure you are warmed up well. - When you warm up, you
get your muscles ready to play. Usually when I get out my flute
I don't sound perfect at first, but after 5 to 10 minuets I'm at my
standard. Make sure you quit warming up about 15 minutes before you
play so that you don't wear yourself out. Keep the instrument warm.