The biggest factor in your credit score is your payment history; at 35 percent of your score, punctuality has never been so important. While paying on time should be your number one priority in raising your number, you need to simultaneously work toward improving the second biggest factor in your score: outstanding debt. It accounts for 30 percent, so whittling down your debt will have a big impact on boosting your score.
If your balances are high, especially compared to the amount of credit available to you, your score will suffer. Calculate your credit-to-debt ratio by dividing your balances by the credit limits on your cards. Your best bet is to never carry a balance, but experts say if your ratio comes out to more than 35 percent then it's time to get cracking at paying down your balances. Throw more money at them each month to get your ratio down as quickly as possible, and always try to pay more than the minimum.