You can put the extra money towards the highest - interest card first, and once that's paid off, focus on paying off the others in
descending order of interest rate.
Rank it in
order of interest rate and then balance.
As I mentioned earlier, I ran the math myself, comparing the «optimum» strategy (which means you repay your debts in
order of interest rate, highest to lowest) to the «debt snowball» strategy (which means you repay your debts in order of balance, lowest to highest).
It starts by listing all your debts in
order of the interest rate.
Furthermore, if you have more than one card balance, you should arrange the balances in
the order of their interest rates.
This consists of applying the amount you have to overpay each month to each debt in descending
order of interest rate.