1) If you haven't already, shadow a vet or three and make sure that this is the right career path for you. Talk to vets about their schooling, their careers, and get their take on the field. It's not all fun and games, and there's a dark side to being in vet med (Debt, finances, cranky clients, cranky clients with no money, cranky clients who want everything free because the vet must love animals, euthanasia, etc).
2) Go to an affordable undergrad, even if it isn't your dream school, and even if it's not the exact degree that you want. Save money, try to come out debt free or close to it. Choose community or state schools over Ivy league. You'll thank yourself later.
3) Have fun in college. Get good grades, but remember, to enjoy yourself too. Seems like a lot of pre-vet people I talk to forget that it's okay to have a social life, and that one or two bad grades isn't the end of the world.