I used Wyzant's online tutoring extensively this summer - I probably spend about $2,000 on the service. They have a tremendous number of tutors, of varying skill levels. The best tutors with the most experience accumulate repeat students. Summer is a good time to get your foot in the door, as their demand is lower.

My approach was to try a variety of tutors for a single subject, for an hour at a time. I give them access to the problems we'll work on together before the session starts. This lets me evaluate both their general skill level and their preparation for the individual session, along with their other traits such as friendliness, clarity, patience, etc. I choose tutors in the midrange of price. Excellent tutors charge moderate ($60/hr) or high prices ($100/hr+). Be aware Wyzant charges a significant fee on top of the listed rate (and it also takes a cut of the listed rate on the backend - a tutor whose listed rate is $60/hr doesn't earn that amount). If you find a tutor you like and expect to give them a lot of repeat business, you can ask them for a modest discount. I think it's worth the investment thoroughly exploring moderately priced tutors in hopes of finding one who is also excellent. There are a lot of mediocre tutors out there, and you do have to be patient.

Wyzant's tutoring was both a lifesaver academically and also shifted my online classes from being alienating to being quite fulfilling. I enjoyed my relationship with my tutor. Having a 1-on-1 tutor is really, really nice.

Many tutors offer tutoring in subjects beyond the ones they list. Some also offer tutoring in subjects they're not actually that great at. You should check in with them about their competency with the specific subject, and even the specific topic, that you're working on.

I don't have a generalised strategy, but Rupert McCallum is my mathematics tutor, and he's very good. He's also recently been given funding from the Long Term Future Fund to provide a subsidised rate ($20 USD/hr) to tutor people who are studying maths in order to work in AI alignment specifically, which is good to know even if money isn't your limiting factor. He'd be my recommendation for the pure maths side of things.

It's really hard because a lot of highly technical fields pay well, so the mere fact that someone goes into tutoring (which tends to pay less) is a kind of minor red flag. 

I'm a lead security developer but I like to tutor because I like the way it keeps my mind fresh. Watching newbies as they exert themselves to tackle basic problems infects me with a contagious optimism.

I usually find students via Upwork, a few a month otherwise it detracts from my already busy day job. If anyone wants to learn Python from an experienced developer and patient teacher, feel free to reach out (just send a message here on LW or respond to this comment). I'm a lot cheaper than the people on Wyzant or wherever, and probably have a lot more hands-on coding experience than whoever you'd find there.

Honestly, I'd avoid being too systematic and money-oriented. Reach out to professionals you admire and ask if they'll mentor you. Before I did cybersecurity I was an ML engineer, and I got started professionally because I noticed a guy at my coworking space had a bunch of cool econometrics books. Turns out he was a brilliant econometrician who knew a company looking for a strong Python dev to help with some ML stuff. He mentored me a lot in the beginning.

Maybe not the most actionable advice, so my apologies, but not organic rather than systematic has been the best approach for me. Good luck!