Interviewing can be a very stressful and nerve-wracking experience but this article from CareerBuilder.com gives some great tips on how to calm yourself and make the best first impression!
Basically, you can’t go too wrong if you prepare for your interview properly. So that means: you know exactly what the job is about; you know who you are meeting with; you know the basic history of the company; you know reasons why you want/will be good at the job and you will leave yourself enough time to get to the interview early!
And remember just to be yourself. 🙂