I have an interview 6/7/11. I have been given amazing advice on here specific to my profession but still panicking. This is my first proper job interview since about 2003 and I've changed a lot since then!
Had my first proper job interview since 2002 last month and got the job, so it can be done! Just be confident, honest and yourself. Remember its a 2 way conversation, not them interigating you! Ask them as many questions as they ask you, you need to know as much as you can about the role and the company so you can make an informed decision if they offer you the job. Wear something you feel comfortable (but obviously still smart) in so you are not tugging at hems/rubbing blisters/etc whilst there. Good luck and knock em dead
Review their website before going. Remember anything obvious eg any awards won etc Ask them any interesting questions about it eg what prompted the decision to focus on the environment as a company if they are making a big splash about it.
Be interested, sit up, look them in the eye, answer after pausing a second to collect your thoughts. Dont forget the question or if you do ask for a repeat (thats allowed!). Definitely pause for a breath, you dont need to answer at a break neck speed. If you look confident they will believe you.
Other than that, have fun. You are allowed to even if you really really want it. Gain yourself some experience at least so even if worst case they say we liked you but....you have something to work with for next time.