Become familiar with the information contained in each of your credit reports. They'll all look very similar, even if you've ordered them from different bureaus. Each credit report contains your personal identifying information, detailed history for each of your accounts, any items that have been listed in public record like a bankruptcy, and the inquiries that have been made to your credit report.
Credit scoring models usually take into account how much you owe compared to how much credit you have available, called your credit utilization rate or your balance-to-limit ratio. Basically it's the sum of all of your revolving debt (such as your credit card balances) divided by the total credit that is available to you (or the total of all your credit limits).