Making extra principal payments is the key, but where does this money come from? The best way to pay off your student loans fast is to budget your money carefully to send in larger payments to reduce the principal. For example, if you have a lot of extra cash left over at the end of the month, then put this toward reducing your student loan balance.
Set up a budget at the beginning of each month to determine how much to pay toward debt, how much to save, and how much to spend. If you can, make the payments to student loans first, and make them automatically. This way you will not be tempted to spend the money on something frivolous once the extra funds enter your account since you will know the funds will be withdrawn for the student loan payment.
Continue living like a college student for a brief period of time after graduation in order to pay off student loans faster. Do not purchase a new car or get a fancy new apartment/house when you start earning paychecks, but instead put that money toward aggressively paying down your debt. It will all be worth it once you become debt free faster and will allow you to easier make larger purchases later on.