Imagine you're a program director (PD) going through scores of ERASes and interviews. What questions would you ask yourself as you assess each residency candidate to avoid big headaches?
1) Can this person do the job? Is s/he competent?2) Will this person "play well with others" and not create complaints from patients, faculty, or other services.
3) Will this person stick with the program and not leave 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, extracurricular activities that demonstrate teamwork, and - if asked - hobbies and reading materials that demonstrate your agreeable personality. For the latter, highlight research projects in the specialty, sub-internships, and knowledge about the program and city.
Simply making sure the PD knows you're not going to cause him/her trouble is at least half the battle.