There is no magic fix for a poor credit report. Fixing your credit takes time, and the process can be long and involved, depending on how many inaccuracies you have. There is no way to remove accurate information; if you find a mistake and the creditor agrees with you initially, but it is discovered the mistake was correct in the first place, the notation will return to your report.
Negatives
Black marks can stay on your record for a long time -- overdue payments for up to seven years, bankruptcies for up to ten. It can be possible, however, if you have made the accounts current, to get the overdue payment marks removed.

On the plus side, time only counts in your favor when fixing your credit report. You may be able to call your creditors, with the help of a credit counselor, and make lower payment arrangements while freezing the interest on the account.
 
Lenders
When applying for new lines of credit, lenders will see that you are attempting to make good on old accounts, and may be slightly more permissive in their lending. There is no guarantee, however, that you will be offered any new credit until all your accounts are current.
 
To fix your credit completely, you will need to pay off all debts, both old and current, and re-educate yourself on healthy financial habits. A reputable credit repair company will provide you with this learning set, as well as give you the necessary tools to gain back financial success.
 
You must do your research on the company you choose to work with! There are many scams out there; remember that a legitimate company will almost never ask for money up front, nor charge you for anything they cannot get removed from your report. Be wary of those promising lightning speeds; it takes at least sixty days to get even one mistake on your report corrected.
 
If you keep these thoughts in mind as you begin the journey of credit repair, you will retain the knowledge of healthy financial habits, and be well on your way to good standing in your credit history.