Although no rank tracker is 100% accurate since results are personally affected by search history and other factors, using a coverage area tracking tool like LocalFalcon or PlacesScout can help give a visual to help you know if your work is helping to improve rankings.
Use call tracking numbers too. You can pulling in the GMB insights via api too. It will allow you to see clicks to call (which is mobile only) clicks to website and clicks for directions. If use a UTM tracking code on Google My Business, you can see more data in analytics.
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.