Pour over the school's website, especially anything related to a mission statement. You want to do all of those things that the school cares a lot about (even if you don't). Go back through SDN's last couple of years of the school's applicant thread and get as much info as you can. Know your application front and back so that you don't get caught either in a lie or confusing that school's secondaries for another one's. On interview day be yourself. If you're sitting down with decision makers then they like you on paper enough to want to get to know you. Use that. Be you, be conversational, be as relaxed as you possibly can. Own your faults and explain them in a truthful way that isn't making excuses. Turn the negatives into learning experiences and show how you've grown from them. Have a modicum of knowledge of current medical ethical dilemmas on the off chance they decide to get philosophical with you.
Read all this then realize that, at this point, no advice will get you accepted. Be as you as you can and blow those admissions people away.