You are there to get a job offer. Give examples of your experience and skills. If possible, discuss how those skills might be applied to a problem that the company is currently having. Show how your previous accomplishments can be repeated at their company. Think before you open your mouth.
Some interview questions are harder than others.
If you get a tough one, be calm and take a couple of seconds to think about what you will say. Be aware of yourself and what you have to offer. You are at the interview because they need to hire someone.