The report “Local Search Ranking Factors” points many factors that can help your cause in the Local Search area.  The report also highlights negative factors that can affect your listing.

The top three factors

1. General Importance of claiming local business listing – all agreed that claiming a business listing is very important to your online Local Search success.  Everyone had a comment and the consensus was that your must start here!  Claim your listing in Google/
2. Local Business Listing Address in City of Search – another high importance factor.  Google maps are becoming accurate in listing local businesses and as such if you are in a suburb of a large city then you are probably not going to be listed in that major city but rather the suburb.
3. Associating Local Business Listing with Proper Categories – another important factor and many say one of the most effective and a well kept secret.

Negative things included:

1. 800 numbers
2. Multiple locations with one phone number
3. Negative Customer ratings.

Read the whole report at Local Search Ranking Factors