Six items to review on your credit report, Part 2: High debt-to-credit limit ratios.

Credit scores typically look at your debt-to-credit limit ratio or utilization in two ways:

1. They compare the balance on one revolving account to your available credit from that lender. For instance, if you have a credit card with a $1000 balance and a $5000 credit limit, this ratio would be 20%.

2. They calculate the total of all your debts on revolving accounts against your total credit lines on those same accounts. So if you have four credit cards, each with a $5000 credit line ($20,000 in credit) and you have a $100 balance on two of them and nothing on the other two ($2000 in debt), this ratio would be 10%.

"In an ideal world, you would want to have [those ratios] under 10%," says Hendricks. "But certainly you want to keep them under 40%. There's no magic number."

But if you're running up a balance of $2000 to $3000 with a card that has a $5000 limit, "that's really going to hurt your score," says Brobeck (executive director of Consumer Federation of America). "And what's worse is running up balances on several cards.

Coming up in Part 3: Collection Activity.