Low limits minimize temptation and help foster manageable payment habits. Put apartment and utilities in your name. Don't let your roommate take over the payment responsibilities and put all the bills in his or her name. It's a chance for you to establish credit. Pay on time.
Timely payments are more important than large lump sums received late.
Avoid too much credit. Having too many credit cards and the opportunity to take on high amounts of debt can actually hurt you when you apply for a major loan. Lenders want to see a reasonable limit relative to your income. One or two credit cards should do it. When it comes to credit, starting early and starting right will save you time and money in the long run.