If you were a program director (PD), you’d be trying to avoid two big headaches as you assessed a residency candidate:
1) Will this person be competent and collegial? A PD does not want to get complaints from patients, faculty, or other services about his/her residents.
2) Will this person leave the program prematurely? A PD does not want to scurry around to fill an open call schedule/ residency slot.
As you approach your interviews, consider how you can demonstrate your competence and collegiality, as well as your commitment to the field and the residency program. For the former, ensure you showcase academic successes, extra curricular activities that demonstrate teamwork, and – if asked – hobbies and reading materials that demonstrate your personality. For the latter, highlight research projects in the specialty, sub-internships, and knowledge about the program and city.
Making sure the PD knows you are not going to cause him/her headaches is half the battle.