Cut all unnecessary expenses.

Lease an inexpensive car or sell any that you went into debt to buy and get yourself a car that costs a few grand. This won't be permanent, but you have to do this for a few years, more or less depending on the size of the debt.

Eat PB&J sandwiches, Ramen noodles, and some McDonald's maybe. If you have a good income then maybe you dont have to go thqf far, but just try ti spend as little as possible to keep a sufficiently comfortable life with roof over your head and food in your stomach. Then use the ridiculous amount of money you save to pay off the debt.

If you make this a lifestyle then you can invest all the money you're not paying towards your debt anymore to invest for the long run.

Self discipline is essential for this, however.