Okay, you asked for advice, here goes:
1. Be familiar with the program at which you are interviewing. Ask questions that show that you know at which program you are interviewing.
2. Be friendly and open. Be nice to everyone, especially the secretaries, support staff, and residents. It's not only the program director's opinion of you that counts. The number one criterion most programs use is "would this candidate be a good fit for OUR program?"
3. Be prepared to talk about yourself, how you decided on your specialty, and how you decided to apply to this program. Even if this program is not your first choice, make it clear that you would be happy to be a part of it.
4. Take the time to listen and understand before responding to a question or comment. This is especially important for applicants for whom English is not their first language. If you don't understand the interviewers, and they don't understand your responses, it will not make a good impression.
5. Above and beyond the program, be enthusiastic about the specialty for which you are applying. We have no interest in applicants who do not enjoy the specialty we have chosen (and for whom it is clearly a "backup" choice). Expect that your interviewers will engage you in discussions about your experiences with the specialty.
6. Read Goro's Guide to the Interview, and other such useful information on this site.
Hope this is helpful!