Another good rule of thumb is to talk to you people you know about which professors to take. And take their advice! It will make taking classes easier and less painful on you! If you do not know anyone like me, go to
http://www.ratemyprofessors.com or the professor grading system on Myspace.com until you meet people at your school.
Don't make the mistake to slack around the first two semesters. I made that mistake and it takes sooooooo much more work to pull up my GPA now and I could just kick myself for it!
Look closely at your syllabus!
For me I tried keep two calenders, one for homework, papers, etc. and the second one is just for social events. Just use one! It may sound like common sense to use one, but it is a lot easier.
Don't be over involved at your school, but don't be under involved. You have to find that happy balance between school (1st priority by the way), work (if you choose), and clubs and organizations.
Have FUN and meet NEW people, not just the ones you live with or have known since high school.
This advice is coming from a college junior so I know the game.