The main thing is to remember to have fun. Talk to other folks there and make some friends. It's not life or death.
Learn from your experiences whether you win or lose. If you win, make sure you understand HOW you won. If you lose, talk to the judges and other competitors, and find out why you lost.
Good luck and HAVE FUN!!!!
"In case you ever wondered what it's like to be knocked out, it's like waking up from a nightmare only to discover it wasn't a dream." -Forrest Griffin