Credit cards and much more
If you find yourself nearing your credit limit, stop spending immediately. If you go over, do everything you can to pay your balance down as soon as possible. Most credit card companies will happily let you exceed your limit because the interest rates they can then charge you are exorbitant. Another side effect is that when you exceed your balance, a note may appear in your credit report, which will lower your credit rating. And, of course, always pay all of your bills on time.