To employ the avalanche method, list your debts from highest to lowest by interest rate. Pay the minimum balance on each, but this time dedicate as much extra as you can each month to the one with the highest interest rate.
Mathematically speaking, tackling the highest interest rates first is the most efficient way to handle debt because it eliminates interest as quickly as possible. The debts that would be racking up the most in interest are dealt with first, so you can minimize interest paid.
However, researchers for the Harvard Business Review find the snowball method to be the most effective because you're more likely to stay motivated if you can see your debts disappearing.
"Focusing on paying down the account with the smallest balance tends to have the most powerful effect on people's sense of progress — and therefore their motivation to continue paying down their debts," Remi Trudel, one of the researchers, writes for HBR.
At the end of the day, the most important thing is to choose a debt repayment method that works for you, and then stick to it.