In gereral, keep your credit as clean as you possibly can and then try to repair any damage that you've done along the way.  Climbing back out of credit problems shows lending sources that you are responsible and are worthy of their line of credit.

A damaged credit rating can follow you around for a long time.  Work hard to repair your credit and it will pay off for you in the long run.

Don't fall for the easy credit rescue scams.  They promise a lot but in the end, most will just take your money.  If it was really that easy, bad credit wouldn't be an issue for anyone.  Beware of anyone who offers a quick fix.