If you have missed payments, get current and stay current - The longer you pay your bills on time, the higher your FICO score will become

Be aware that paying off a collection account will not always remove it from your credit report - It will stay on your report for seven years, if you don't take aggressive action. (We give you the specific action to take in our e-Book)

Keep balances low on credit cards and other "revolving credit" -  High outstanding debt can seriously affect a FICO score.

Pay off debt rather than moving it around - The most effective way over time to improve your score in this area is by paying down your revolving credit. In fact, owing the same amount but having fewer open accounts may lower your FICO score.

Don't close unused credit cards as a short-term strategy to raise your score - A credit card that has been closed appears on your credit report for 7 years and the FICO score can not distinguish between you closing it or your creditor.

Don't open a number of new credit cards that you don't need, just to increase your available credit - This approach could backfire and actually lower your FICO score.

If you have been managing credit for a short time, don't open a lot of new accounts too rapidly - New accounts will lower your average account age, which will have a larger effect on your score if you don't have a lot of other credit information. Also, rapid account buildup can look risky if you are a new credit user

Do your rate shopping for a given loan within a focused period of time - FICO scores can distinguish between a search for a single loan and a search for many new credit lines, in part by the length of time over which inquiries occur.

Re-establish your credit history if you have had problems -  Opening new accounts responsibly and paying them off on time will raise your FICO score in the long term.

Note that it's OK to request and check your own credit report - This won't affect your score, as long as you order your credit report directly from the credit reporting agency or through an organization authorized to provide credit reports to consumers. Beware of websites that are not affiliated with the credit bureaus, as this will lower your FICO score.

Apply for and open new credit accounts only as needed - Don't open accounts just to have a better credit mix — it probably won't raise your score.

Note that closing an account doesn't make it go away - A closed account will still show up on your credit report, and may be considered by the score.