1. Dress appropriately.
2. Don't chew gum; turn OFF your cell phone before you go in!
3. When you shake hands with someone don't "dead fish" them - shake their hand firmly.
4. Don't fidgit; toss hair, say "um"
5. Stress your positives - at this point you have little job experience so use what you have in your life - responsibility; civic minded; on time; dependable!
6. Remember to ask when you can expect to hear from them.
There is no reason not to carry a small notebook or portfolio with questions / tips / things you want to remember with you and refer to it --
GOOD LUCK!