Your credit report is the most important piece of information that potential lenders use to determine whether or not you are a good risk for them to lend money. Every account you currently have is listed in the credit report along with information about your payment history. If you have missed payments or if you have been late, this information is available to lenders when you apply for a loan.
Any accounts that you have paid off in full are also listed and this is looked upon favourably. If you have filed for bankruptcy, though, this single item will probably mean your application will not be approved. Bankruptcy is a serious entry on a credit report and should be avoided whenever possible.
You should check your credit report on a regular basis to know what creditors are reporting about you. It is also possible there may be mistakes in your credit report you do not know about.