What sort of things besides grades are they looking for?

Medicine, or any other profession within the medical field, is beyond the academics. Yes, you need to be academically driven and show high academic capabilities but what differentiates one candidate from another is their personality, their experience and their level of professionalism. How you portray yourself at the interview and the manner in which you answer and respond questions can demonstrate your confidence and ability to handle difficult scenarios, because that is what they will attempt to test in the interview. They will be looking at how you respond to possible real life scenarios, and possibly, what you already know from a medical aspect. They will be looking at your interests and experiences beyond academia, ie. the jobs or hobbies you have as they are looking for a well rounded individual with a wide range of social and personal skills, that can work independantly and within a team and whom can balance their personal and academic life.