Credit scoring, by default, is confusing, and in these times, it can really throw you for a loop. Whether your credit is determined "good" or "bad" depends on a simple three-digit number called your FICO score—the higher your score, the lower the interest rates.

Generally, a score of 680 and above is considered good enough to get you loans and cards at the best interest rates. But because the economy is experiencing a crunch, lenders are setting the bar even higher, meaning you now want to shoot for a score of 720 or greater, says John Ulzheimer, president of consumer education for credit.com.

So how do you do it? Start by pulling your report. You're entitled to a free report from each major credit bureau once a year, so three total. Unless you're a victim of ID theft, I suggest you spread them out, pulling one every four months or so. Go to annualcreditreport.com and get yours, then pinpoint what exactly is dragging your score down. Some possibilities?

• A high debt to credit ratio. "You want to get your revolving debt to no more than 10% of the credit limits on the cards you have," Ulzheimer says. If you're a good customer, a fast way to bring that ratio down is to call up your lender and ask for an increased limit. Tell them you want a policy increase, which means they raise the limit without looking into your credit file.
• Late payments. The due date on your bill isn't flexible, and one tardy can hit your score hard. Pay a couple of days early just to be safe.
• Shopping around. Store cards may seem like a good deal—15 percent off!—but that savings will be negated later when they bring your credit score down and your interest rates up. Every inquiry into your score has a negative impact, so just say no.
• No credit. Maybe you never took out a card, and now that you want one, you don't have a credit score or even a report. That's considered risky to lenders. Start building credit with a secured card, which basically accepts a deposit in exchange for a line of credit in an equal amount. Just be sure that the card you choose reports to all three credit scoring bureaus so you're not wasting your time.