My two cents on interviews is that they are easy. You need to be presentable, you should be confident in what you say, and you must prepare ahead of time using questions from the internet (although you already know what you'll be asked - why the field, why this hospital, why did you study abroad if your an FMG or general questions about your school if you're an IMG...). Follow the above three principles and your answers will be clear and sharp.
Of course, there is always the occasional crazy person who will give you some weird case and expect you to save the world. In my experience, that is not usually the case so be relaxed and confident, practice your answers, know what messages you want to convey and you'll do excellent.
Finally, I must mention that this is based on my experience in surgery and radiology. While they represent two extremes of the interview spectrum (surgery - more stressful interviews, radiology - more relaxed interviews), the best advice I can give is to ask someone who interviewed in your specific field during the previous year.
Well if you made it this far you're more or less done. All that is left is to rank your programs. Good luck : )
The Residency Interview
Application & Interviews