8. Do not use your card for luxuries
Even if you own too many credit cards, avoid using them for luxuries. Big purchases means you need to shell out huge amount of money to pay off their interests. So, stay away from buying luxury items from your credit cards. Instead, use your debit card or cash for big purchases. This way you will know how much you have already spent and you will not be easily tempted to buy unnecessary things. Even if you have to, you can choose a card that offers good cash back rewards.