First thing to know is paying off debt is pretty minimal in raising your credit.
Credit is really the opposite. The more open credit you have the better.
Three factors are most important. On time payments, length of credit history, and available credit limits.
If you are young it will just take time for #2.
You'll want to pay your debt off entirely if you want it to raise quickly. Then you'll save up $300-$750 and apply for a secured card. Its important to not use more than 30% of your limit.
As you use the card it will raise and you be able to get another card. This is a big decision and you should do it when you're ready.
After you have no debt and a few lines of credit remember to use them and pay them. No missed payments.
Score should shoot right up and you'll be able to get better rates.