Brightly Colored and/or Unique Clothing. Wear clothes that you are comfortable dancing in and that show off your lines nicely. Remember that bright colors are more likely to catch a choreographers eye, and if you can do this, then your dancing will keep their attention on you.
Take Every Class. Some dancers like to skip a class or two that they have never taken, but that doesn't help you grow as a dancer. If you have never taken a tap class, conventions are a great place to try it out. Just slip on your jazz shoes and try to get the jist of the movements.
Front Is NOT Always Best. If you've been to a dance convention you know how there is always a rush to the front of the stage. All these sweaty dancers pack in next to each other so they can be as close to the choreographer as possible. Then when it's time to dance, they end up kicking and punching each other while performing the movements. Try taking a middle-to-back spot. This less dense area will give you room to perform full out. Trust me, full out dancing is a lot more admirable than giving the girl next to you a bloody nose.
Don't Get Frustrated. Conventions are supposed to be hard. You're going to be trying movements that are unfamiliar and awkward and that is GREAT! Treat conventions as times for expanding your repertoire and improving upon your own style. Have fun, and who knows, you may find that "Funky Jazz" class is something you really like, and you want to do a "Funky Jazz" solo next year.
Ask Questions. Can we go over that part again? Can you have the front half kneel, it's difficult to see the moves back here? What would you like to see our faces do? Choreographers love getting questions like these because it shows that you are interested in their material and improving yourself.