Going into my second year at Michigan majoring in computer science. I definitely have some interesting tips for people just starting college.
First off, alcohol is everywhere, make sure you ease your way in to it (if you want to drink that is; plenty of people don't!). You do not want to end up in the hospital. Limit yourself to one or two beers/shots per hour until you know how your body handles alcohol, and then you can start to drink a little more.
Second, leave the door to your room open as much as possible (obviously not while you're out or sleeping), especially early on. Wander your hall and pop your head into any open rooms, introduce yourself, etc. Make sure you find and befriend someone who has some kind of Nintendo console for the inevitable Smash Bros matches later in the year. If you are that someone, be open to having lots of friends!
Third, explore your campus! A girl and I wandered around UM's north campus a couple of nights during our first week and familiarized ourselves with the area and just had a good time. Also, if you know your way around, you can show the campus to your family if they visit.
Fourth, having a girlfriend is possible during college, I did it. However, long distance relationships (assuming fidelity) suck.
Fifth, respect your roommate (if you have one). Don't play loud music all the time, keep the room at least somewhat clean, don't hog the TV, use headphones for computer audio, if he's going to sleep, turn off your lights or at least try to angle them off of him, don't take his food unless you have permission (my roommate and I kept our own food, but kept the fridge stocked with pop/water and shared that. basically if you went home for a weekend you picked up a couple cases of pop). Oh ask if he has any allergies that you should be aware of and try to accommodate those!
Last, take some intro classes that are completely random but sound interesting. I took an introductory logic class through the philosophy department and loved it. I also took an introductory programming class and decided that's what I want to do for the rest of my life lol.
Oh, bring lots of food. Pop-tarts, candy, chips, nuts, popcorn, instant noodles, cheezits...Whatever you like to snack on.