“Avoid it completely,” Mr. Pizor said. Anything a credit repair company can do, he said — including disputing inaccurate information found on your credit report — people can do themselves, at no cost.

If negative information listed on your credit report is correct — for example, you have stopped making payments on a loan or credit card balance — there’s little you can do to remove it quickly, the consumer bureau says on its website. Negative information typically remains on your credit report for at least seven years.

“Beware of anyone who claims that they can remove information from your credit report that’s accurate, current and negative,” the bureau says. “No one can do that.”

Consumers can try negotiating with lenders on their own, Mr. Pizor said, perhaps by offering to make a full or partial payment on a bad debt in exchange for an agreement by the lender to stop reporting the delinquent account to the credit bureau. It may not work. But it won’t cost you anything. If you reach an agreement, he said, “get it in writing” before making the payment.

An alternative is to seek help from a reliable, nonprofit credit counseling organization, the bureau says. Credit counselors provide advice on how to manage your money, and can help you develop an affordable plan to pay down your debt. Some counselors offer advice at no or low cost.

Here are some questions and answers about improving your credit:

How can I find a reputable credit counselor?

Michelle Grajales, a lawyer with the Federal Trade Commission, recommends finding a counselor who can meet you in person. A good place to start looking is on the Department of Justice’s website. (The site lists agencies approved to counsel consumers who are considering filing for bankruptcy, but you don’t have to be contemplating bankruptcy to use them.)

Other potential sources are the National Foundation for Credit Counseling and the Financial Counseling Association of America.