As someone who has just finished her first year at college, I felt I needed to share some advice with those of you who are about to start your first year. This is based on my experience at a small town, Christian liberal arts university, so not everyone's experience is going to be the same.
Don't take 8 a.m. classes. If you absolutely, positively cannot avoid them, only take one a semester. Otherwise, you will die. I practically did last year.
Don't take once-a-week evening classes. Or really, any evening classes. You'll have to miss out on other activities and you'll just hate yourself for taking a class when you've likely already had a long day.
Make an effort with the people on your hall, in your orientation group, in your classes, etc. Other freshmen are trying to make friends too! Some are just more shy than others; if you're one of the shy people, try occasionally to speak up first. Otherwise, just be willing to respond and get to know people.
Don't buy your books from the campus-affiliated bookstore (whether online or in person). Use Amazon or BookByte. You'll save a ton of money. (Unless you need a special online code or a special edition; get those directly from the college then.)
Get plenty of sleep. Sleep is invaluable. It'll keep your immune system up, make you a kinder person, and help you do better in classes. Even if your friends rag on you for going to bed earlier than them, do it. It's better in the long run.
If you don't make it to breakfast in the caf often (or ever, like me), keep breakfast foods in your room. Even easy stuff like granola bars, PopTarts, fruit, bagels, cereal, and so forth. Breakfast makes your day so much better.
Give family and friends your campus post box address. Mail makes your day so much better. I love getting packages from my parents and random letters from friends and all the books I get as a book blogger. (The CPO staff know me really well since I'm always coming in to collect packages. I'm on a first-name basis with a lot of them, and they don't even ask if I have a package anymore when I come in; they just walk right back to get it.)
Use Quizlet to study for tests. It's a lifesaver, guys. I wasn't doing too well on my art history tests, so for the third and fourth ones, I made Quizlets. I got a 98% on the third test and a 94% on the fourth.
If your dorm has a kitchen, make sure to buy a few key cooking utensils (pots, pans, spatulas, etc). You'll want to cook occasionally, trust me. Caf food gets old real fast.
If you don't have a car, make friends with people who do. Most are pretty willing to take you to get groceries and toiletries and what-not. It's also nice to offer them money for gas if it's out of their way or not.
Find ways to get out of your room and/or off-campus on weekends. You'll get tired of your dorm and the campus if you never leave. Hopefully your friends will be willing to go shopping, or to a movie, or out to eat or SOMETHING.
Take advantage of any cool events your school has. We have a sitcom that we film (that's been Emmy-nominated), multiple plays, Sophomore Musical, and the Highbridge Film Festival. It's been so much fun to go to big events.
Your major is important. Choose something that you can make a career out of. But your minor? Your minor can just be something you enjoy. I'm minoring in history for this reason. It doesn't matter nearly as much as your major and important electives you take.
Take care of yourself. Don't take all the classes that will overwhelm you in one semester. Make sure you have time for friends, books, movies, insert-something-fun-and-not-stressful. Believe me, you'll want that down time, especially towards the end of the semester.
If you get a significant other, don't neglect your friendships. Freshman year relationships rarely last (I know of two that didn't make it past first semester). Your friends will be there for you longer if you treat them right. Even if you're head over heels for some guy, don't put him ahead of your platonic relationships so quickly. And I'd also advise not getting into a relationship until you've been at school for at least a month and probably for a full semester.
Have fun, but make good, solid choices. Don't feel like you have to go along with the crowd.
But it's okay to make mistakes. You're in a whole new place with a whole bunch of new people. You're bound to screw up every now and then. Allow yourself to learn and move on. College can be one of the best and most formative parts of your life. You're going to make it through.