One of the main things that I have found that most businesses miss, is the local or free listings. Have you spend some time looking for the type of things your clients would be doing to locate your products or services? Have you looked at what they'd be seeing? Have you looked at the type of websites that appear are they things like the Yellow Pages directory? or Truelocal website? Google maps and more? Take some time out to do the searches and see what comes up. Take the time to go and register your business on those sites.
One other tip - Take the time to respond to feedback on those sites, particularly if something negative has been posted, business image is important and it's important to take that time to respond accordingly -- correct any incorrect information, reply to any negative feedback constructively, offer to fix the issue however is appropriate for the issue and continue building your online presence. Most of these sites offer a one way response and you will not be able to remove negative feedback - and this is realistic, negative feedback is something that happens in all businesses from time to time. Offering an alternative and addressing the issue shows your prospective clients that you care enough to make an effort and also shows a real side to you and the business.