Google Refrigerator (Photo credit: Aray Chen)
Ranking on Google Places is similar to organic SEO in that you need links called citations. Or NAPs.
City, State, Zip
You will also want to put a geo site map on your site as well as a .kml file.
Remember you are ranking your Google Place to come up into the "seven pack". It will list your URL if you claim your Place page. There are ways to optimize your Place that can help your ranking into the "seven pack". But like organic you need those citations.