Interview tips?

So I have an interview today and I'm kinda nervous. It's the first job I've applied for that requires a degree and I don't feel confident about it at all. I don't feel well spoken and like I sound professional so knowing that I'm interviewing with other people with degrees that may sound more intelligent makes me nerves. I've interviewed before and did get the jobs speaking normally but something about this feels different. Do you think it's just in my head and I'll do fine? Even reading answers to interview questions from the interview makes me feel like I can't recreate answers like that without sounding dumb. Any advice?

Really hope this make sense to someone.

usa jobs
usa jobs resume
usa hotel jobs
usajobs
usa jobs federal government
usa job in ksa
usa jobs
usa jobs login
usa jobs gov
usajobs.gov
www.usajobs.gov
usajobs.com
usajobs
usajobs.gov official