To be a Doc in the US you have to ...
First keep your record spotless. No memberships in political or criminal originations. No reference to drugs at all. Stay away from anything controversial. Do not join anything that is ethnic or political in nature. You might get away with membership in a political parties org but that's taking an unnecessary risk. Not matter how innocent it might seem to you it is possibly controversial and could hurt you in interviews. Join all the clubs you want after you become a Doc.
Generally pharmacists do extremely well in Med school. I would recommend this route to anybody who is not brilliant in school. It means taking longer to become a Doc but it will be a huge help down the road. Both in deciding if you really want to become a Doc and in getting to that goal.
Get into a decent college. It helps if your major is Pre-med or biology. Chemistry is not a bad major either. There is no requirement so technically you can major in Phys Ed and still be eligible. What you major in WILL affect your interviews. So it is important to either have a major that will help you in Med school or be very good in interviewing to get around the damage done by a major not associated with medical students. Every year hundreds or thousands make it into med school with majors like Law, English lit, etc. You may want to do this to bulk up your grades if you are extremely well suited to another major.
After doing very well through your bachelors. Just getting your degree will not be enough. You do not have to be a strait A student either. The better your grades the easier it will be to be accepted into medical school. Involvement in certain organizations can help as well. Anything medical, intellectual or that strikes a chord with the interviewer is good. Avoid anything controversial. If if the interviewer agrees with you politically Doctors are supposed to be objective.
Start studying for your MCATs as a freshman in college. If you do not make at least a certain score on them and these are very difficult exams you are not going to get into Med school in the US. The better you do the easier it will be to be accepted. If you are female, a minority or have a special story you can make it with respectable MCAT scores possibly. Depends on how many of your exception are applying that given year and what their scores are like. There is a program or at least was several years ago that allowed certain minorities to get extra help and acceptance of minorities with less than minimum scores. The program gave them extra time on tests, sliding scales on exam scores and other help to promote diversity among doctors. Still nobody glides through Med school. Do poorly on the MCATs and you will not get accepted anywhere for any reason.
Start preparing for your interviews in your jr year at the latest. Research medical schools. Find ones that you like and will you think accept you. Find out what their min MCAT score is for acceptance. Something you won't find listed anywhere. It's something you'll have to dig out of people. By your senior year of college your already applying at schools. You are unlikely to get interviewed until you've taken your MCATs so take them early. The more time you have to interview the better. You are unlikely to get picked first interview. Build a field of ten schools. 3 of your favorites but also at least 2 schools of last resort in case you do not do as well on the MCATs as you thought you might.
Once you've taken your MCATs you know your fate possibly. If you did acceptable on them you have a chance at getting into medical school.
You should have several interviews lined up. At least 5 bare minimum. Realistically if you can afford the travel try to get at least 10. Dress well.