Reducing the interest rate on any credit card with a balance is another great money-saving tactic. Transfer your balance to a card that offers an introductory rate of zero percent for the first 12 months. If you transfer a $3,000 balance that incurs 15 percent interest to a zero-rate card, you'll save at least $388 in interest payments the first year.

But there's a big if here. Credit-card issuers that offer the zero rate reserve their best deals for consumers with the best credit scores, so yours needs to be at least 760 (find out your FICO credit score at myfico.com). If your score is below 760, make it a priority to nurse it up by paying your bills on time, even if you're making only the minimum payment. That simple show of responsibility accounts for 35 percent of your FICO score. Another important step is to reduce the outstanding balance on your cards.

Here's the caveat with transfer deals: You must pay all your bills on time, or your zero rate could swell to at least 19 percent. And don't put any new charges on the card, because the zero rate usually applies only to the transferred money. If you can't pay off the entire balance by the end of the year, transfer it to another zero-rate card—but limit your transfers to one per year, to keep your credit score from suffering.