Similar to defending your reputation, repairing your reputation begins with making sure the positives about you are put front and center. Having a deliberate strategy and schedule of action is critical. Naturally, sticking to the plan and modifying as necessary, are assumed.
Do you have the time? The objectivity? The discipline?
Having a third party assist can make the difference between being successful and believable, and not.
Also, having a third party act on your behalf with take-down notices, following up with the search engine, social networking and social media sites, using tools to find the negative comments and requesting cached copies be deleted...it can be cumbersome, detailed, labor-intensive and frustrating.
Hire an advocate who is dedicated to seeing results on your behalf.