Most everyone who optimizes for Google Local (aka Google Maps) is familar with David Mihm’s excellent and oft-referenced Local Search Ranking Factors. In that document, and in many places where local results are analyzed, it’s clear that getting your business/website into more listings, in a consistent fashion is a very good thing. Yet, somehow, this obvious tactic has gone missing from many GG Local optimization recommendations. Either that or it’s so obvious that no one feels the need to mention it. Whatever the case, it’s available now.
http://www.seomoz.org/blog/one-dead-simple-tactic-for-better-rankings-in-google-local