interviews are usually about character - interviewers want to see what kind of person you are, with respect to the way you carry yourself, the way you communicate, and the way you respond to questions. they don't care to find out you memorization skills, so do yourself (and the interviewer) a favor and don't have any answers memorized. trust me, they can tell if a response was prepared rather than spontaneous. duke is an elite school, so they're looking for smart people. on the other hand, don't let tuesday come without ever practicing. sit down with a few people, and have them ask you random questions. see how you do. don't get too bogged down though - they're not holding a 30 min interview to decide how smart you are - your academic record takes care of this. like i said, the main purpose of the interview will be to find out who you are as a person. so be ready for a lot "personal" questions.