Relevance

How well does your local listing match what someone is searching for?

Reason one why your business information should always be fully detailed and accurate.

Distance

How close are you to the person searching for a particular term?

Remember relevance will always be the stronger signal. If a business is further away from a searcher’s location, but is more likely to have what they’re looking for than a business that is closer, Google will rank it higher in local results.

Additionally, if a user doesn’t specify a location, Google will calculate distance based on what’s known about their location.

Prominence

How well known is your business?

Here’s the exact wording on ‘prominence’ from Google…

Some places are more prominent in the offline world, and search results try to reflect this in local ranking. For example, famous museums, landmark hotels, or well-known store brands that are familiar to many people are also likely to be prominent in local search results.

Prominence is also based on information that Google has about a business from across the web (like links, articles, and directories). Google review count and score are factored into local search ranking: more reviews and positive ratings will probably improve a business’s local ranking.

Your position in web results is also a factor, so SEO best practices also apply to local search optimization.

Your business’s overall organic search presence is a ranking factor when it comes to local.

So ultimately, all of your regular, everyday SEO practices that you do to boost your rankings, whether on-page or off, apply to local too.

Customer reviews

It is interesting to note that as Google has confirmed that customer reviews and ratings are ‘probably’ factored into local search ranking.

Experts always figured this was true anyway. Moz previosly found that review signals are 8.4% of the overall ‘local ranking pie’.

Accurate and complete Google My Business information + accurate location data + positive customer reviews + traditional SEO tactics = good local ranking (possibly)

Source: https://searchenginewatch.com/2016/04/04/how-does-google-determine-my-local-ranking/