Years ago your credit score was a big secret, known only to a select few such as your mortgage and credit card companies. In 2000, Fair, Isaac Co., the major supplier of credit scoring software, announced they would begin sharing credit scores, also known as FICO scores, with consumers.

What is a credit score? A credit score is a tool used by credit grantors to determine your ability to repay your debts. The information in your credit report is compared and evaluated against tens of millions of other consumer credit reports which gives you a credit score or number ranging from 350 (highest credit risk) up to 800 (lowest credit risk). A higher score means you are less likely to make late payments or default on the credit extended to you. Your credit score will change as the information in your credit report changes over time.

Following is a short overview of the five major categories of credit information that are used in determining your credit score and guidelines for scoring higher.

PAYMENT HISTORY (35 percent)

Paying your current bills on time is the single most important factor in obtaining a high credit score. This category includes credit cards like Visa and MasterCard, retail accounts, installment loans such as those for a car or education, loans from finance companies, and home mortgages. Also included in this category are matters of public record such as bankruptcies, liens, wage garnishments, and collection accounts. The key to a higher score: Pay your bills on time!

HOW MUCH DEBT YOU CARRY (30 percent)

This category considers the amount of debt you owe on your various credit accounts. If you've "maxed out" your available credit, this could indicate that you are overextended financially and won't be able to make your payments on time or repay your debts completely. This category also examines how many of your accounts carry balances and how much money you've already repaid. Closing accounts with a zero balance does not generally improve your score in this area. The key to a higher score: Keep your credit card balances low.

LENGTH OF ESTABLISHED CREDIT (15 percent)

The longer you've had credit accounts the higher you will score in this area. The age of your oldest account and the average age of all your accounts are used in determining your score. Old accounts that have gone unused are also considered. The key to a higher score: Establish good credit and keep accounts active.

APPLICATIONS FOR NEW CREDIT (10 percent)

Opening multiple credit accounts within a short period of time represents a greater risk of becoming overextended. Each time you apply for credit an inquiry is made into your credit history and these inquiries show up in your credit report. A high number of credit inquiries will lower your score.

Some inquiries are not considered in your score. These include: requests by you for your credit report, inquiries from companies for pre-approved offers or companies that already do business with you, along with inquiries from potential employers. Some requests for credit are treated as a single inquiry especially when you are shopping for the best loan rate. The key to a higher score: Only apply for and open new credit accounts when you need them.

YOUR CREDIT MIX (10 percent)

This category examines the types of credit accounts you have and how many of each. Can a person have too many accounts? Yes and no. It really depends on whether you have an established credit history or no credit history at all. The key to a higher score: Open credit accounts only if you intend to use them.

Don't despair if you have a low score or are just beginning to establish credit. Your credit score will change for better or worse depending on how well you understand and use these five keys to your advantage in planning your financial future.

James is editor of "TO YOUR CREDIT", a weekly free newsletter to help you manage your personal finances.  Subscribe to the newsletter by visiting http://www.yourfreecreditreportnow.com. He is also author of  "Identity Theft - How to Avoid Becoming the Next Victim!" available at http://tinyurl.com/bc45