There are two books than will really help you out.
-Med school confidential
-getting into medical school by kaplan
they go over all aspects of applying to med school, I really wish I had found these books when I was a freshman! (you can get used copies on amazon or half.com for like $5)
MCAT:
You want to take the MCAT by the end of your junior year. You'll want to start studying 4ish months ahead of your mcat date. But make sure you complete all of your required med school prereqs first.
Research:
I personally do not think research is necessary for med school acceptance. I think clinical experience is much more important (unless you want to be a research physician). If you have your heart set on research, then pick something that interests you. I dont think it needs to be health related, but it should be in a science.
Applications:
you will submit your applications a year before you hope to start medical school which is usually the summer between your Jr and Sr. year. I think its average to apply to 10-12 schools.
Classes:
Take upper division sciences. Biochem, Genetics, Cell Biology, Anatomy (either comparative vertebrate or human), Physiology, Embryology. I would also suggest taking a reading/writing intenstive english course. Med school requires A LOT of reading, so they like to see that you can survive a course based upon it. Plus I believe it will help you with your applications since you will be a better writer than someone who just too freshman english 1 and 2.
Dont forget to do fun stuff too! Get a minor in something just because it is interesting to you! Be involved in an extracurricular that has nothing to do with health or medicine because you love the people. Whatever. Just make sure and dont forget to enjoy college. In 3 years, your personal statement will be more fun to read that someone who spend 3 years in the library and as president of the premed club.