One of the main thing I do to prepare for an interview is to study a little background about the company especially the mission and the vision.. so I can determine if my objectives are aligned to them. The company's vision is very crucial for me, I always ask, "Do this company have a compelling vision that I'm willing to be a part of?" Another preparation I do is my "Me, in 30 seconds" power statement.
sometimes, I call it as my elevator pitch. You can have this question as your guide, "What does this company needed to know about me in just 30 seconds?" And definitely, the last tip is to be confident and to always be yourself.