The answer is everywhere.

Yelp, referrals, hardware stores, showrooms, at work...

Yelp
Reviews and pictures tell a lot about a tradesman on Yelp. One natural problem most highly rated are either higher priced or not available for a long time or not responsive. I found the shower door installers, and duct cleaners there. They all did amazing job.

So far so obvious. Let's see where the risk reward ratio gets tricky.

You definitely need licensed contractors for mission critical tasks such as electric, plumbing, water proofing. But for other tasks such as painting, taping, tiling not so much.

Referrals
I was lucky with one of my referrals, a carpenter for opening the walls. The guy was working during business hours in a construction company. My tasks were all additional work for him after business hours and at the weekends. Later seeing the quality of his work, I asked if he had some friends doing other tasks. Sure he had, he got quotes and timelines from them with quick turn around. In the end they all work together many years and know the quality of each other's work. I prefered paying cash to most to get even lower prices. Sure, I did not accept all quotes blindly, did number crunching to meet the ends.

At a shop
Despite all these options at some point of renovation, I was in a dire need for a tile guy for couple tasks; original bathroom contractor got hospitalized during his europe trip while the one of two bathrooms he was responsible for was not completed. Another for renovation the fireplace. And the guest bathroom shower needed tiling and a shower base. For the last one I was ready to give up on due to the budget and timeline.

While trying to choose tiles for the fireplace at a tile shop with large selection of installed tiles, I saw a tile guy doing his job, tiling. That was quite a rare opportunity for multiple reasons. First of all, you can walk and see his work all over the showroom. I asked him if he can help me for my fireplace project. He asked me to talk to his boss. I did not care about his boss at all. I asserted again by saying "do you want some cash for this additional work?". Well, the awakening happened. We cut a very good deal there. The guy told me later he has been working there many years and installed all those tiles himself, removed when tile is out of stock and refreshed with newer models.

Ordered a very special and large tile from Florida. And the guy showed up as promised. Did a perfect and clean job. It is quite a blessing working with people who truely like what they are doing. Good job gets rewarded for sure. I gave two more tasks: completing the other bathroom and guest shower I was ready to give up on. Results were amazing with an unbeatable price. Now the same guy is remodelling my realtor's bathroom based on my referral.

Sometimes they find you

At a Sunday, after we moved in to our remodelled home, while standing in the neglected front yard, a tree trimmer young guy approached and asked if we needed trimming our palm tree. Never thought palm trees needed care at that height until I lift my head. (Hell yes, lets get rid of that ugly dry branches) but how much? $40 if I remember correctly. We also asked if he can remove the ugly bush, we cut a very good deal again. After a while the need to remove the concrete at our backyard showed up (when my 3-year old fell down and hurt himself at the backyard again).

Do not want to digress but why would people even put concrete on their backyard which needs to be place to enjoy greens and relax. And the huge cost of removing it. Anyway, that has to be fixed.

It does not even make sense to ask a tree trimmer about removing concrete. But we did. Suprisingly, he was interested. He needed some time to calculate logistics etc. Ended up with by far the best quote compared to other concrete removal quotes; saving me couple thousand dollars.

At work

Everyone starts getting to know that you are doing remodelling due to disapperances during lunch times and conversations. It is a great to ask people who already did remodelling for referrals.

Bigger companies like mine have also internal boards full of recommendations, earlier quotes, tips for working with them. Chose my painter and kitchen installer from there.

As you can notice, extending the quest beyond online search yields very good results since neither does every good tradesman have a listing online nor do they care to deal with that.

My way of finding tradesman is exactly how my grandfather would approach the problem, yes, old-school but super cost efficient especially if you have resources to pay by cash. In my case, I was again lucky to have a friend to lend me some and have made some financial decisions yielding good results.