I live in a small town and I have a few friends and neighbors who really depend on search results for their businesses. Unfortunately, since I worked as a contractor at Google for a while they think that I have some inside knowledge, which I don't (I specialize in AI and the semantic web).

Here is what I suggest to them as general advice: write great content that people might enjoy reading even if they may not immediately become your customer; don't repeat the same information on multiple web sites using different domains; use the Google web tools to find ways to fix your HTML; write a blog on your (one) domain and write as much interesting and useful material as you have time to create.

I feel fairly confident giving this advice even if it does involve more work for my friends. Long term, providing good content is key.