The advice that everyone has given you has been great!
Just a few extras to tag on:
1. If you're in class, or studying, and you don't understand something, don't be afraid to ask your professors for help! That's what they are there for.
2. Every college/university has a career center. This place is a blessing in disguise. It can help you find great jobs, I know it helped me.
3. I know it has been said before, but time management is KEY! I know so many freshman who flunked out because they did not know the meaning of this (think of your GPA).
As someone who is about to graduate from college (Class of 2003

), I wish I knew half of this stuff when I was entering college.
All in All, good luck!