For, example, some people pay a little more than the amount due on their mortgage or auto loan each month. The extra money paid is credited against the principal. However, you need to choose wisely when deciding which bills to prepay. But the size of the debt shouldn't always be the determining factor. Consider the interest rate.
Most people pay a much higher interest rate on credit cards than on their mortgage.
Don't be too eager to get rid of this reasonable rate. Remember also that your mortgage interest is tax deductible, while your credit card interest is not. It makes more sense to get rid of your high rate, non tax-deductible interest loan first. The same goes for your auto loan. Take a look at your total financial picture.