You can organize your loans by the amount you have left to pay - smallest to largest - and start knocking them out one by one. That's the snowball method. Or you can choose to organize them by interest rate, paying off the loan with the highest rate first and so on. That's the avalanche method.
Use this calculator to see how both methods can be applied to your debt. The calculator can also apply an additional monthly amount to the balance with the highest rate. When that balance is paid in full, the balance with the next highest rate will be paid down. This continues until you have snowballed through all of your balances and your debt is paid in full. Click the "View Report" button for a detailed look at the results.