Seems weird to think about this considering i'm 25 (am I old yet? lol), but looking back there are things that I would have done a little different, and things that I am very happy I did.
1. First off, LIVE IT UP. I was always told this by everyone that "college will be the best years of your life." While there is still much to come in life, college is a great time. Instant access to so many friends and activities and the first sense of real freedom in life. Now this doesn't mean be a degenerate who has a 1.0GPA and gets drunk every night of the week, but finding a balance. You will meet some of your best friends here.
2. Choose a degree that will give you access to a prosperous career. I had many Liberal Arts College friends who have majored in things from Historical Communications to Women Studies. They are now struggling to find any career, let alone one that will pay off the large debt.
3. I would have learned more about everything. Be naturally curious. While there is a lot to learn in school, there is always more to learn. Read read read. I haven't started reading again until recently. There is SO MUCH great information out there at our fingertips and I wish I would have started reading earlier. Especially about personal finance and investing/real estate. This is NEVER taught in school. Be able to budget. Know how to save more than you spend. Know the difference between an asset and lability. You have to get a grip on money if you want to grow any amount of wealth in your life. Debt will hold people down their whole life because they don't want to learn how to manage their money.
4. INVEST. This can be in real estate or stocks. Now I do not recommend trying to be the next Warren Buffet and picking your own stocks. That's wasting time and majority of the time, money. Pick a low cost index fund and start putting money in it. Time is sooooo important for investing. Even though during college you can't add much, you can add some (you should have some form of on campus job for play money and a summer job). Also, get that employer 401k match if that's possible (this would be a couple years from 20). The rest of the money you have can be put towards real estate. But real estate shouldn't start without have your general finances under control (point 4)
5. Travel! Maybe not for everyone, but the traveling around the world I have done has been so amazing! Buy experiences, not objects. That new shiny thing you bought won't be that cool in a month, but I constantly think about great trips with great people. And some may say traveling is super expensive, but I disagree (depends on what we say is expensive). But traveling abroad and staying in Hostels is cheap (~15$ a night) and you will meet great people. And flights abroad can be found for round trips of $250 if you know what you're doing. Again maybe not for everyone, but this is my thought.