I'm a college prof. TwentyHz's advice is very sound. Just my own thoughts, redundant repetitions, and additions:
Watch your money. Apply for every grant and scholarship you can think of.
Balance, balance, balance. On the one hand, college is about more than academics, I know that; on the other hand, you can make friends and party anytime, but once you finish school, you may never get the chance to go study those subjects the same way again. Don't become such an academic hermit that you miss out on all the other things going on, but don't get so swept up in those other things that you let your classes slide.
Seek mentors. The disciple chooses the master, not vice-versa. Talk to your profs one-on-one every chance you get; stop by their office hours, you're not interrupting anything, most of them sit there reading a book till a student shows up. The class is just the jumping-off point; if you're really interested in a subject, you'll get a lot more out of talking to a prof about it than you do in class.
You may say to yourself "all my classes are irrelevant, all I want to do in life is play bass." Do not listen to yourself. When I was an undergrad, all I really wanted to do was direct plays. Now I'm a historian. Guess when the last time was a directed a play. BE CURIOUS! There is no such thing as a subject that is not worth learning about.
Do not double-major or add a minor unless you absolutely have to. A person who does two majors does not get any more education than a person who does one; all they really do is fill up their schedule with so many requirements that they never get to take any electives. As a result, they never get to explore a subject just because it's interesting. BE CURIOUS. Use your few years in college to EXPLORE.
Valid reasons to double-major would be if you're planning on a career that requires both (e.g. arts management, and you major in both art and business), or if there's a course you feel you MUST take that is closed to non-majors.
Don't worry too much about the employability of your major; that's a myth. Focus on the skills you learn doing that major, not jobs that require the content of the major. Law school deans would rather see English, History, and Philosophy majors apply than pre-law. Again, there are some careers that require a particular degree (engineering, for instance). Many do not. I majored in theater and my first job (with full career options ahead of me, if I hadn't gone back to grad school) was in marketing. I had learned great communication and writing skills. Lots of majors teach you to communicate better than a communications major does.
At first you'll be jumping in a gazillion extra curricular clubs. Don't overcommit, slim it down to maybe two that you're really interested in.
Getting along with roommates is important, but it need not be best-friends. It does need to be setting and respecting reasonable boundaries and expectations of each other.
Beware food in the dorm and clean up after yourself. Nothing makes dorm life as much fun as infestations of ants, roaches, or mice.
Stay healthy, eat, sleep and exercise.
If you must drink, do so moderately. Nobody I ever met was happy they spent their youth binge-drinking. The headlines are full of stories of college students (especially freshmen) who died outright from alcohol poisoning, or who tried to walk home from the party smashed and never got there, washed up in a river days later, or who lost all sense of judgment and wound up either raping someone or getting raped.
Most people I know who left school never returned either.
