There is not an easy way to repair credit. It takes a couple years to repair damage that you have done over the years. If you are too far in debt, look at all your options. If you are just behind a little and able to catch up, you are at a good start. First I recommend what I did. I had to file bankruptcy 4 years ago due to my husband being laid off, my vehicle being stolen, and my remaining car had the engine fall out of it, all right after we just bought a new house.
After the bankruptcy was final, I got 1 credit card with $500 limit (and paid a $89 annual fee) and set it up to keep the balance at around $100. I used it to buy gas, paid it immediately so that there was constant activity, but the balance stayed around $100. Just make sure you make all your payments ontime. I have been doing serious damage repair, and now have my credit score above 700. One other thing I did was use my banks auto bill pay. I set everything to go out automatically. I even averaged my utitilities and notified the utilities what I was doing, so some times during the year, I will have a large credit, but I will never be late. I also have everything going out the same day I get paid so I never really see the money. I pay everything every other friday, so some time during the year, I get way ahead, and have a whole free paycheck, to either enjoy, or pay an extra mortgage payment. Just remember it wont happen over night. Some credit card companies offer free credit scores too. WAMU credit cards offer a monthly credit score, so I use that to watch my progress. Its slow, but steady.
Good luck, I know its a hard hole to dig out of.