I often get asked how med school and residency works. It's not really clear or intuitive and most people get their information from extremely accurate TV shows like Grey's Anatomy and Scrubs. As someone who finally understands it, and I can assure you I did not until probably this year, let me do a bit of explaining.
For pre-med, I've given a decent explanation here, so I'll leave it alone. I'll move on to first year. This year is all about minutia. It has been said that you spend the first year learning a language, and that is more or less accurate. Particularly first year, your life is to learn basic science, basic science related to medicine. This is like getting hired as a lawyer and then being asked to spend a year learning how books get made. You learn new fancy words, with no idea how to use them or what they really mean. You hear about things that sound important, but don't really exist. The kind of thing where your attending* sees primary syphilis and is like, "It does exist!", and he's been doing it since the pre-antibiotic era. You definitely learn a lot, but it's mostly useless or won't stick. The major utility of this year is to drink and hook up with your classmates.
The summer between 1st and 2nd year is the only summer med students get. This is a hard concept to understand for the rest of the working world, who assumes school is school and schooooooooool's out.for.summa! It's not. And most people work this summer, doing research. Lawyers get paid around 30,000 for the summer. We get paid around 3,000. If you have a good grant. Again, a good time to drink and sit by a pool and regret hooking up with your classmates.
Year 2. This is pretty much the same, but they get your ready for the wards**. You do things like see standardized patients; paid actors who pretend to be sick and then give you feedback afterward that is always the same, one good thing, one bad thing, and "how do you think it went?" "I think it went about as well as it could go considering you aren't sick and I've seen you tending bar at The Back Saloon. We were both there last night. Didn't have a bum knee then, did you?". We learn physical exam, interviewing skills, basically all of the stuff that teaches you how to diagnose the fact that you need to order a cat scan.
At the end of this year, you take Step 1. This is the MCAT for residencies and is a super painful test. More about it here.
More on year 3 and 4.
*Note: An attending is the head doctor (Dr. Cox, if you will) who runs the show, makes final decisions, and pimps the shit out of you.
**Note: The wards is the name for actually being in the hospital. Clinics is a synonym.