Getting healthy credit requires a three step process. One, stop acquiring any more debt. Two, get rid of your outstanding debts. Assuming you are taking steps to get your debt under control, then you can move on to the third step: repairing your credit rating.
This is going to take some time. Every time you are late on a payment, it hits your credit report for two years. That means once you are free and clear, it will take two years for your credit rating to get fully healthy.
That may sound like a long time. But there are ways to affect information on your credit report that don't have to do with your missed payments, actions that won't take two years to have an effect.