Periodically contact your credit card companies and give them an earful. Don't hesitate to complain about the interest rate you're paying. If you're a good customer and haven't been late or delinquent the credit card company will very often listen to your beef and proactively reduce your rate.

Let them know that in the competitive consumer-credit environment of today you have options and offers from other companies at more competitive rates or that you're contemplating leaving them by transferring your balance to a competitor's card if they can't help out with a lower interest rate.

It's only a five or ten minute phone call and it can pay off big time especially if you're carrying a large balance.