For most construction related stuff: on the job with someone with 30+ years of experience. You can only learn it by doing it but it's good to have someone telling what you should and should not do.

I work in tech and the best resource for learning how to work in tech is to be asked the stupidest question you could ever fucking possibly imagine by somebody that makes 17 times your annual salary.

Electrician in NA, the International Brotherhood of Electrical Workers (IBEW) has an apprenticeship program which is generally considered excellent. I doubt youd find much better training.

Time. No matter what you do, putting in the hours of practice gives you the experience and exposure needed to get better. Whether it's art, music, tech, cooking, language, or whatever, there's truly no substitute for spending time.

Beyond that I think it's good to use a broad approach where you switch between variety of things like naive exploration, studying masters, theory education, etc. (It's no good to just study music theory, for example, you need to also be learning existing songs and playing around with your instrument in an intuitive way. I think the same concept can be applied to many other skills )

Knitting: it really helps to start with an actual human teacher, but people can self-teach themselves using YouTube only. After you get the basics down, YouTube is great for learning a stitch you’ve never seen before. And that’s pretty much all you need to start reading patterns. Anytime you come across something you don’t understand, YouTube to the rescue. There is also a great community site called Ravelry for pattern discovery, discussion, and yarn information.

For aquarium fish keeping, YouTube (fishtube) was pretty good but it's been getting worse because of all the ai sloptube. Probably a friend or local aquarium club is better if you can overcome any shyness.

For semihydroponic plant keeping YouTube is still okay except everyone is going to try to sell you specific brands of grow lights and fertilizers. We have a decent community here on Lemmy too.

Old cookbooks from the beginning of the industrial revolution

Programming: The internet in general. But not AI.

Hobbies: Books.

Hobby is modern boardgames.

Best resource is the review and tutorial videos from Shut Up & Sit Down (SUSD)

https://www.youtube.com/watch?v=A5fM0cOxD2k

https://www.youtube.com/channel/UCyRhIGDUKdIOw07Pd8pHxCw

Edit: Changed link from potatoes, to a review of Innovation. One of the best card games available.

Money.

Blog posts and the arch linux wiki lol

For comp sci and music I've found access to a teacher who can help create a plan to achieve your goals and office hours or similar once or twice a week to point you in the right direction when you get stuck is the most efficient but also the most expensive route. Next best is books and online tutorials but without a plan and direction it's easy to waste time or get stuck on some concept or technique.

I am in professional consultancy. You learn by fucking up, and try again just to fuck it up again (less intensely ).

My trade, bioinformatics/computational biology... a ton of software documentation, tutorials, guides, vignettes... And some programming books here-and-there (which the authors released online for free). There are Master's programs, but realistically hands-on researchers overwhelmingly learn by doing. The field is just too small and scattered... The downside of this approach is that my field is traditionally criticized for having little to no adherence to software engineering best-practices

My hobby, there are like 2 websites (one is a dedicated webpage, one a GitHub wiki) that contain literally everything one needs to know about them

Apprenticeship is the only way, but you need books to help pass the exams.

Sacramento State courses were at one time considered the best: https://owp.csus.edu/operator-training/courses/correspondence-courses/wastewater-courses/course.php?sectionId=1947&has_child_courses=1

I'm even if they aren't considered great anymore, doing the correspondence course which costs $50 and is a series of online multiple choice questions gives you 90 training hours towards your renewal requirements which is more than two years worth here.

I understand operators these days prefer the WEF manuals: https://www.wef.org/publications/operator-training-manuals/ Perhaps they kept up with the standard exams better.

On the engineering side I love the WEF MOP, especially MOP 8: https://connect.wef.org/s/store#/store/browse/detail/a2nRP000000oa6jYAA

We joke that Metcalf and Eddy is our bible but it's the most basic starting point in research. I think people take the joke too literally sometimes:

https://www.mheducation.com/highered/product/wastewater-engineering-treatment-and-resource-recovery-metcalf-and-eddy.html?viewOption=student

you won't ever learning much of anything without real world experience.

reading books, videos, coursework, etc, will never give you experience.

for some reason people can't seem to understand this, and our entire education system basically ignores this.

Canning I use things like the Ball website or things like the National Center for Home Food Preservation for safe recipes. A lot of...YouTube stuff is not safe, or use very outdated methods like canning in the oven or wax or just turning them upside down and back upright.

Apprenticeship.

music, and the best resource is a microphone so you can record your practices and listen to them.

There will come a point where you plateau and need not just a teacher but a mentor.

Someone on tap who can answer your questions and give critical, constructive, trusted feedback.