Don't be one of those people that eats Ramen Noodles all the time! I hate to be preachy but one package of Ramen Noodles is about 80% of our daily value of sodium, wow! There are so many healthy options and I know that especially now in this economy food is expensive but you can still find good values. Trader Joe's, for example, is my savior; their food is really good, affordable, and most of it is good for you. Check out their website, and sign up for their e-newsletter --- http://www.traderjoes.com/index.html
Do network; form as many meaningful connections with people as possible. College, like the job world, is all about networking, or at least laying the groundwork for some serious networking in the future.
Don't wait until you have the bare minimum left in clothes to do laundry. You never know when you will have a fashion emergency (and a "do" within a don't, do separate your lights and darks and delicates).
Do invest in nice bedding, and wash it weekly no matter where you live. Nice, soft, quality sheets mean a good night's sleep. They also mean that whoever you do bring back to your room will no doubt be impressed with your maturity, sophistication, and cleanliness (and he/ she is more likely to come back).
Don't burn the candle at both ends; in other words, make sure you get enough sleep, or college will kick your butt!
Do attend class as much as possible. Most schools require you to attend a certain percentage of classes to attain a certain grade no matter what you get on your mid term and final. This also ties back to networking as well; you may meet a lot of people in class who could help you in the future so it does benefit you to crack a book and go.
Don't go to class in sweats or pajamas; it's just wrong on so many levels. Sweats is something you wear in your house when your relaxing or chilling out. It doesn't look professional to colleagues or the professor when you walk in to class in that type of attire. At the very least, wear jeans a nice top. Also I don't know/ haven't seen any guy that has attracted a girl wearing sweats in class, and I don't know any girl that has attracted a "quality" guy in class wearing sweats or pajamas.
Do form as many long lasting friendships as possible because some of the friends you meet with and bond with in college will be your friends for life.
Don't forget what college is all about. Have fun because that is a big part of the college experience, but don't lose sight of why you are really there. College is also a major time for self discovery, you will, no doubt, learn a lot about yourself and what you need and want from life (on a side note, this self discovery will continue throughout your 20's).
Do take risks because they will almost always pay off and you will regret it later if you don't. Risks are a necessary part of life because they make you a more well rounded person, you will be more open minded, and people will respect the fact that you took a chance even if it didn't work out how it was supposed to.
Bonus: Don't be like me in this next regard; do learn how to dance in college if you don't already know how; it will so come in handy later in life, and throughout your time in college. You don't have to take professional lessons, ask a friend to teach you, it can be a great bonding experience, and it's fun to learn.