Keywords that have existing relevancy to the GMB are best to start with.
GEO GRID PROXIMITY OPTIMISATION KEYWORDS
1) Always try to use the Primary GMB category as one of the keywords
2) Relevant Website Product Page Keywords The easier way to do this is to ensure that they have a page on the website for their keyword. (Example: Plumbing repairs page with the keyword in the title and H1 tag preferred. If not just in the title.) site:URL Search, the second check is to ensure they appear in GMB Maps in position 4-20
3) Then the GMB sub-categories (only if relevant and not too similar to the primary category)
4) Search Phases: Consider the Products/Services that are most valuable to your business, what are the “Jobs to be done” that a consumer is wanting your business to provide.
Note: Typically we look for 5-7 Keywords, however, don’t add them for the sake of it, it is best to think of what is most valuable to your business.
You cannot rank for other brands/trademarks. Ie Google My Business / Adwords
To see the keyword selection process in action, please refer to this training video:
Selecting Keywords Video Training for Staff and Resellers