I don't think your interviewers will have a completely different set of questions if you're OOS vs. IS. My guess is that they'll be more curious as to why you picked their school compared to an IS student. Talk about how your ambitions will further their mission statement (whatever it may be), and how your strengths as a student will make you a good fit in the student body--obviously elaborate more.
But this is what worked for me:
Take out a sheet paper (or start a word document) and start listing the "common" questions:
- Tell me about yourself
- Why did you choose this school?
- Why medicine?
- Etc.
Google the top 50 medical school interview questions to get you started.
Talk yourself through these questions and start jotting down key points to each answer. Don't write your answers down as if you're writing a presidential speech, this will work against you if you do. The point of this is to get an idea of what you want to say.
Now, practice your answers
out loud whenever you get a chance. The goal is to make sure your answers sound natural/conversational. Some answers sound good on paper, but sound really stupid or robotic when spoken. It helps to have a friend record your answers and critique your performance as you go.
For each answer make sure you hit all the main points. Challenge yourself and see if you can hit those main points in different ways. I had about 5 answers for each 'big' question I could think of (why this school? Why become a doctor? etc.). On interview day I just mixed and matched depending on the situation.
Your answers should reflect the school's mission in some way, so be sure to memorize the school's mission statement/visions/goals. If you're interviewing for DO schools, then be well-versed in the osteopathic tennets, the history of osteopathic medicine, and Andrew T. Still. For example, most DO schools heavily emphasize primary care, so be sure to mention an interest in those fields IF YOU HAVE THE EXPERIENCE TO BACK IT UP. Don't say you're interested in "x" field when you have 0 hours in it. It raises a huge red flag.
Practice breathing exercises, AND SLOW DOWN during the interview. Talking like you're an auctioneer won't help you. Brief pauses in your answer, if done correctly, will make it seem like you're putting together a well-thought out answer instead of going for the first thing that comes to your head. Stop saying "umm" and "like."
If you're given an ethical question, start off by considering both sides of the argument and THEN take a side. Be sure to support your argument. For all other questions, just answer truthfully and try to relate back to your pre-med experiences.
Make eye-contact, smile/laugh (when appropriate), nod, sit up straight, make hand gestures as you talk. Reflect the tone of the interviewer and know when to be serious or slightly relaxed. Never make it seem like you're intimidated. Your goal is to take control of the conversation.
Don't give your interviewers a wet, wimpy handshake. Stand up straight, extend your arm before they do, and give them your firmest handshake while thanking your interviewers. It will go long way.
These 2 videos calmed my nerves before interview day (they are quite long, but it helped):
And watch some videos on MMI interviews to get a feel for them.