There are a handful of ways that Google associates a business with relevant keyword phrases.
When you registered the business in Google Places, you should have added Categories which were apropos of the business - as many as are appropriate. Beyond category names, the description field and additional fields can be used to list products/services/amenities associated with your company -- all of these lend keyword relevancy.
On you company's website itself you should also add keyword phrases which describe what your company does -- producs and services.
After doing all those things, links/citations may enable your company to rank in relation to other companies targeting the same keyword phrases.
It can take months for citations from various sources to impact your Google Maps listing. Submission of information to a directory that feeds into Google Maps may take a while before Google recieves and update from that info provider.
Submitting and updating business profiles with top online yellow pages as well as other business directory sites may all contribute to your presence in Google Maps.
Further, other online promotional efforts can help you, such as issuing press releases with links, developing widgets or other content that goes viral, doing blogging, as well as various social media campaigns.