Just relax! I interviewed at UHS in January and the great thing about interviewing there is that they accept most of the students that they interview. You'll get a tour, etc. of the school, an OMT presentation, and there are plenty of opportunities to ask UHS students questions. The atmostphere really put me at ease. At the interview, they asked me about my study habits, motivation, etc. I would only suggest to know of a couple current topics in medicine as well as why you went the D.O. route. Just have fun chatting with those you interview with; it will make it much less stressful. Good luck!