Have you ever wondered what makes your credit score go up? What makes it go down? And what really has no effect at all?

Then check out this free booklet from MyFico.com, Understanding Your FICO Score. When people say "credit score" it can really mean one of several different types of FICO scores, all slightly different. So it's a good idea to know how it is calculated. And how to make it as high as possible (with credit scores, high is good).

Unfortunately, many people think they can't do anything to change their credit score. But that's not true. Because your credit score is dependent on many factors. Such as:

• payment history (late payments lower your score)

• how much you owe (the more you owe, the lower your score - most people don't realize this)

• how long you've been using credit (so keep your old accounts)

• new accounts (too many new accounts are a "red flag" and lower your score)

• types of credit (shouldn't be all credit cards)

So even if you've had problems paying on time, you can still raise your credit score.

• The #1 goal should be to pay your bills on time - come up with a system so you make payments on time. There's nothing worse than getting penalized because you forgot a payment. If you do, call your lender right away, and ask for them to help you get current, and remove any late fees.

• Then, stop applying for more credit, especially if you will be getting a loan for a major purchase. Shopping around is OK. But not if you do it all the time. And not if you keep getting more and more credit.

• And try to pay down your existing debt as much as possible. You'll pay for a high amount of debt in several ways - higher interest rates, lower credit score, more likely to miss payments. Pick one account and try to pay it off as quickly possible. Then move on to the next account. And keep going. This is called debt snowball.

• Don't close old accounts, either. Having old credit is good. And having unused credit is good too. So unless there's a clear reason, keep those old accounts open.

And then there's credit repair. Which gets a bad rap, but can work if done right.

First, you need to get a copy of your credit report from www.AnnualCreditReport.com. Then make sure everything on there is accurate. If not, dispute it.

And there are ways to get even legitimate credit problems removed from your credit report (and you don't need to do anything illegal, or even "shady". You just need to know how to ask). There are lots of credit repair companies out there that will charge you a lot of money to fix your credit problems. But most people can do it themselves. It's not hard. A simple credit repair manual can help you learn how to do it yourself.

To get your free copy of Understanding Your FICO Score click here. Have any other good credit repair tips or resources you would like to share?