I think this is how most homeowners hire this type of people, they either "have a guy" or they ask their friends/neighbors if they "have a guy". I have an HVAC guy who is miles better than the HVAC company with ~50 techs that I had come out before I found him. But if I needed some plumbing work done, I'd ask my neighbors, since I've never gotten plumbing done before.

If neither of these they fall back to advertising, door-to-door sales, classifieds, google reviews.