First impressions are crucial. When you go, make sure your body language is constantly upbeat and positive. Shake his/her hand at the beginning and end of your interview. Thank him/her for considering you. Just remember that you'll be selling yourself. You need to PROVE that you would be a positive addition to their staff. Verbiage is also a good thing to keep in mind. Avoid "uh, umms...." and silence. Sometimes interviewers may throw tough questions at you, but don't let it scare you. Use words like "Absolutely, of course" instead of saying "okay" repeatedly. Address him/her as "Yes sir" or "Yes ma'am." That said, you should be golden. Good luck to you!