Congrats on your success with your client! Unfortunately, it's going to be pretty hard for anyone to give you reasonable advice without having a listing to look at, and the search query you're talking about. If you'd like a general list of ideas on what to work on to help get your client the top spot though, my favorite overview is here.
New advertising option:
A review of your product or service posted by a Sterling Sky employee. This will also be shared on the Sterling Sky & LSF Twitter accounts, our Facebook group, LinkedIn, and both newsletters.