An interview is a step in the job application process.
Before the interview, review the job description and identify transferable skills and experiences that meet the position's requirements. Prepare examples that demonstrate these skills. Learn about the organization by reading its website and related news articles. Note questions about the organization you may want to ask in your interview. While each interview will likely be different in feel and content, there are many questions for which you can prepare.
You only have one chance to make a first impression - make a good one!
For your interview, know where you are going, how to get there and your commute time. Arrive ten minutes early so you have time to compose yourself. If, due to unforeseen circumstances, you will be late, be sure to call your interviewer. In the interview, be confident in your presentation. Be genuine, be yourself, say what you believe.
You should also plan to follow up with your interviewer. Within 24 hours, write a personal thank-you note including any information you want to add and reinforce your interest in the position. If you have met with more than one interviewer, you do have to write to each one (be sure to get everyone's business cards). Handwritten thank you note leave a lasting impression. Many students use Wheaton College note cards.
After the interview, use the interview experience to clarify your goals and interests. What did you learn about yourself and the company? What would you do differently next time? Without being overly critical of yourself, make note of this.