Your Google Business Profile is the single highest-leverage marketing asset most local businesses own, and it is free. It is also the one most commonly left half finished, because the sign-up process lets you stop as soon as you have a name, an address and a phone number.
Google is trying to answer one question when someone searches: which nearby business is most likely to satisfy this person right now. Every field you complete is evidence toward that answer. Every field you leave blank is evidence you have not supplied.
Categories: the field that decides everything else
Your primary category has more influence on what you rank for than almost anything else on the profile. Choose it as specifically as the list allows. A business set to the generic option competes against every business in that space; one set to the exact service competes against far fewer, for far more relevant searches.
Add secondary categories for services you genuinely offer, but resist stuffing them. Categories you cannot actually deliver on will bring enquiries you have to turn away, which wastes your time and disappoints people who then leave.
Services: list them individually
The services section is repeatedly ignored and it is one of the most useful. Each service you add is another phrase your profile can be matched against. If you offer eleven things, list eleven things, each with a short description in the language customers actually use.
A profile that lists only your trade name cannot be matched against the specific problem someone is searching for. That is not Google being obtuse; it genuinely has nothing to work with.
Photos: more than you think, updated more often than you think
Add photographs of completed work, your team, your vehicles and your premises. Real photographs, not stock. Customers are trying to work out whether you are a real, settled local business, and a profile with two blurry images from three years ago does not answer that well.
Update them periodically. A profile that is visibly maintained signals an active business, which matters both to Google and to the person deciding whether to call.
Service area versus address
If customers come to you, show your address. If you travel to them, set a service area and consider hiding the address. Getting this wrong is common and it affects how and where you appear. A contractor showing a residential address with no service area set is limiting themselves to searches near that one point.
Hours, including the awkward ones
Keep them accurate, and set special hours for holidays. Wrong hours do not simply lose a booking. They send someone to a locked door, and that person usually does not try again. It is one of the few marketing mistakes that actively creates ill will.
Reviews: the part that never finishes
Reviews influence both ranking and whether a human chooses you from the three options they are shown. Recency matters, so a business with forty reviews from four years ago can lose to one with twelve from the last three months.
Respond to all of them, including the negative ones, calmly and briefly. Prospective customers read the responses more carefully than the complaints. A measured reply to an unfair review is more persuasive than a page of five-star ratings.
Posts, products and Q&A
Posts expire after a week, so they are only worth doing if you will keep doing them. The Q&A section is worth seeding: you are permitted to ask and answer your own common questions, and it is better that you write the answer than that someone else guesses at it.
The honest summary
None of this is difficult. It is a couple of hours of careful work and then periodic maintenance. It is also the reason a competitor who is not better at the actual job keeps appearing above you. If you do nothing else from this article, complete your categories and services properly.