Interviews become easy when you're forced to do them over and over.
Make sure to shake the interviewer's hand and give a warm greeting; prove you're excited to be there (even though it's loving Chick-Fil-A). Don't be scared to take your time answering the questions, but do it with confidence and use a nice, loud presenter voice. Don't mention negatives, only positives that you make sound like negatives.
At the end of the interview, ASK QUESTIONS. That makes you stand out. I know it sounds dumb; you'll already know everything going in, but just ask something that's going to make it sound like you care about the position.