I disagree with the "not much to prepare" advice. Unless you're a natural with interviews, you should spend several hours answering MMI questions in front of a video camera and watching yourself to see how you can improve. You should also go for mock interviews at your career counseling dept. as many times as allowed even if this means going there every day or two. And practice with as many people as possible, even people with no special knowledge of medical school interviews, including family members and other applicants. (Source: it worked for me.)