David Mihm, a search engine optimization expert, has published the results of a survey on local search engine ranking factors for Google. The survey, which is based on own experiences and interviews of other experts, especially considers the latest general changes of the Google search engine algorithm as well as the latest changes like the integration of local search and Google+.
The results consist in 90 positive and 18 negative possible factors. The term possible needs to be added because Google ranking factors usually are a secret and the results by this are empiric. Here is the list of the Local Search Ranking Factors.