-Try to call the schools you're applying for and see if you can schedule multiple interviews for a trip to save money.
-Be prepared to talk about every activity/honors/EC you've listed or referened in your PS. I once had an interview go for 1.5hrs that involved going down the list @_@
-Be prepared to answer the general questions: "Why do you want to become a doctor? What qualties do you have that you think will allow you to be a good doctor? Why our school? What can you add to our X? What do you do in your free time? (Don't say anything nerdy) Which specialty? (very few ask this) Why DO? (if applicable))
-Send thank you letters and LOI's
-Use SDN's interview feedback
-Be liberal with your interviews until your first acceptance. Then be picky.