If the area is crowded enough, google adwords might give you insights into what is searched for the most.

For example, if you have a restaurant in london, you would like to go for a domain that matches what people search for if they want to find a restaurant in london.
But as there are multiple ways of searching for restaurants in london (dumb example, i know...), you might want to know what phrasing is mostly used!

Read this article for structuring your URL https://moz.com/learn/seo/url

put keyword in url and title that's it this is the one and only golden method.