When a small amount of money is used to pay interest of a debt, and a bigger amount is used to pay the real debt, than your goal of reducing your debt is going to be achieved faster.
Reducing your interest rate, at least on a few percentage points, will allow you to put more money towards your debt every month. While saving $50 or $100 every month may not seam much, if you use those savings towards paying your debt, it might be a great help.  The greater your debt, the more you will save by reducing its interest rates.

These suggestions will help minimizing the money sent to pay interest, and maximize the money sent to pay principal.

• Asks your credit card company for a lower interest rate – it seams too simple, but it often works. Call the costumer service of the lending company and let the representative know you are shopping around for better rates. If you receive a pre-approved credit card proposal with a lower interest rate, let them know about the offer and that you are considering the change, than see if your current company can match the offer. The credit card industry is very competitive nowadays; you will realize that this simple approach may reduce your interest at least a couple of percentage points, and frequently even more.
• Prioritize your debt by interest rates – to reduce the interest you pay to minimum, focus on paying out the bills with highest interest rate first.  Keep your bills up-to-date, paying at least the minimum monthly amount of each one of them. Try paying an additional amount every month to the highest rate ones.