It is obvious that everyone is tense on interviews. If you simply make yourself to feel nervous, surely you will do much better. Keep in mind also that it's easier said than done for the interviewer as well.
In small words be upbeat and positive. Never be negative.
About these 64 questions and answers are designed to be as particular and realistic as possible. Go and check each one, if you do this, and follow the principles of successful interviewing presented here, surely you're going to do very well