Repairing your credit is certainly something that you can do yourself, but it requires a lot of time, work, and organization. Correcting just a single error on your credit report can take several hours when you consider obtaining copies of your report, writing a dispute letter, and communicating with creditors. There are advantages to hiring professionals who are familiar with the Fair Credit Reporting Act and understand credit law to do the legwork for you.
I applied for a home loan - wasn't approved - the loan company works with people with subpar credit though. She gave me list of action items that needed to be done. She figured it would take me about a year to take care of it all. Gave me a deadline of 1 year out. I sat down did all her action items in a week - waited 30 days, credit jumped to 620. She got an approval on a home loan but it wasn't ideal. Waited another 30 days, credit was 651... she said we could get an ideal approval with a credit score of 640. I don't know how, but I was so happy. signed on house at 3 months instead of 1 year. The loan officer couldn't believe it! I now own my home, have lived in it for over a year. Love my house!
This is easier said than done, but reducing the amount that you owe is going to be a far more satisfying achievement than improving your credit score. The first thing you need to do is stop using your credit cards. Use your credit report to make a list of all of your accounts and then go online or check recent statements to determine how much you owe on each account and what interest rate they are charging you. Come up with a payment plan that puts most of your available budget for debt payments towards the highest interest cards first, while maintaining minimum payments on your other accounts.