Overcoming bad reviews can be challenging, espcially for someone not experienced in reputation management. Soliciting positive reviews is a great first step to building a reputation. Some review tips include...
Overcome, but don't delete
Negative reviews are a fact of life. Overcoming them is the key, with the conversation on your own turf. Deleting, hiding, editing... are all great ways to turn a moderately painful situation into a massive nightmare.
People appreciate honesty
You can gain more street cred by admitting a mistake and fixing it than pretending it never happened or downplaying the importance.
Solicit and share feedback
Ask customers how you're doing and share the results, even when they're less than stellar. Fix things, and ask them again. Ask them to post reviews on public review sites. The key is to build a strong foundation so that the inevitable dings in the armor are nothing major.