If you’re afraid you'll keep spending as long as there's room on the card? Call your credit card company and request your credit limit be lowered. Keep at it. Card companies will try boost up your credit lines so you spend more. Tell them "no" each time they try.
Be realistic about your spending habits. You can do what you want, but you can't do everything you want. You're going to have to make some choices. Whatever you choose is going to cost some money. You need to understand you can't have everything and you have to understand there's consequences. At some point there needs to be a reality check in terms of what things cost. Most students have no idea.
If you bust your budget on something you really, really want to do this week, make up for it next week. If you find that you must go out to dinner and a movie one week, spend the money; be satisfied with the decision, and commit to staying home, eating at home, and not making any other purchases the following week.
Plan ahead for big expenses. Whether it's a road trip with friends or a car insurance bill, if you know a big expense is coming, start putting some money aside to pay for it. It's a lot easier to set aside $50 every month than to come up with $300 when the bill is due.
When it comes to dorm or apartment expenses, contact your roommate before the semester starts and divvy up expenses. Decide who will bring a refrigerator and who will bring a microwave, etc. This way you avoid duplicating purchases and excess spending but will still have all the conveniences to make college life easier.
Most of the big expenses are at the beginning of the school year. Buy books as you need them. That will spread out expenses. Don't forget to check out prices from online bookstores. They may give you a better deal than the campus bookstore. Buy used books whenever possible. Check e-bay or half.com with the ISBN number of the textbooks you need. You can usually get this number from your college bookstore, and the prices are usually a lot lower than what the bookstore will charge.
Don’t forget, too, that when the semester is over, if you have a book you don’t think you’ll use ever again – Thermonuclear Physics, The History of the Doughnut, etc. – sell them back to the school or list them online. This can be a really easy way to make a little cash at the end of the year.
It's very difficult to say 'I'm in trouble and I need $2,000' or 'I spent my student loan money'. Screw up some courage and phone home. The longer you put it off, the worse things get. While your parents might not be thrilled that you’ve been so careless with your money, we’re willing to bet that they’ll probably be ready to help out – after a few moments of lecturing, of course!