Having more credit cards doesn't mean more credit score. You need to have only a few credit cards and you must use them often as you can but do not keep any balance in any of your credit cards. Pay up your credit cards every month before the due date and if you can't afford something, do not charge it to your credit card and pay it bit by bit. This is very damaging for your credit score even if you are paying the required amount mentioned in your credit card statement. You must pay up fully whatever the amount is mentioned in your credit card statements. Do not buy something if you feel you can't pay it off in one shot when the statements come.