Why are you concerned about your credit score? Looking for a house? car? You need to pull your credit score as others have stated. Clean up any defaults. If you have any questions, ask specifically on each default. If you don't have any, you're doing good. You can't fix late payments. They will remain there for 7 years. Make sure you pay them on time. Keep any revolving accounts less than 40%. Keep at least three continuous forms of credit and you want them to report to all three credit bureaus. This can be a credit card, mortgage, car payment, ect ... If its a revolving account, make sure you keep a small balance.
If you can't get a credit card becuase past credit cards or anything sent to collections try getting a secured card. they use your money as collateral and it helps build up your credit. Most banks will require at least 300 min.
Your credit score is actually a measurement that companies use to determine if they can make money from you. If anything, people with a lot of debt who always make payments on time often have high scores. Get more debt, then make regular payments. Remember, your credit score is not a measurement of how much money you have but of how much money creditors can make from you.
