Answer :

Formulate possible responses in your head already so you know what to say, know what type of questions they will be asking you so you can get an understanding of what to expect, try not to be nervous, make eye contact at all times if possible or if you feel comfortable
Ok, since you asked and there is an open spot, from what I learned from myself, books, and other people, here is the best ideas:

1. Before even going to an interview, scout out the area and make sure you have your clothes, transportation,etc ready because this brings self confidence in yourself.

2. Before taking the interview, drink water and take a mint because again, it brings self confidence and you are not afraid if people are looking at your face if there is something wrong with it because you prepped yourself.

3. Before the interview, make a list of possible questions they may ask and write responses to them. Go ahead and look online for the type of questions they give because other interviewed people sometimes post the questions they ask.  

4. Go practice in a mock interview with a friend(s) so that you get used to the idea of people asking you questions...maybe have them formulate their own questions.

5. Try to stand out and make a good impression. You have no idea of how many people get hired because they were "different" and stood out in a good way.

6. Practice videoing yourself but do not get frustrated. Just see on how you can improve.

7. Get a good nights rest and try to refrain from eating unhealthy foods and coffee the night before.

8. Remember that you are "advertising" yourself to an employer and your future is on the line, so take it seriously as if it was a real interview(i know its for school)

This is most of what I can think of...