When I have an interview and haven't had one in awhile I try to come up with possible questions an interviewer may ask and mull over in my mind how I would answer them. If you have someone who is willing, ask them to do a mock interview with you and give feedback.

The big thing is to remember you're selling yourself. Although it's good to present an area of weakness if asked, don't volunteer it. If they ask if you have experience with something and you do not, don't simply answer "no" but let them know you are willing and able to learn new things. Use good eye contact and make sure your handshake is firm.

I get worried about being late to interviews so I arrive early. I will then call a friend to calm my nerves while in the parking lot as I don't want to walk into the building too early. A walk around the parking lot may not be a bad idea if it's not a place where the interviewer may see you.

good luck!