That was an example but it could be woo.
Go down a level and find a class or collaboration group on the object level thing you want to do.
That's not realistic advice. You can't simply take a single class because you're interested in it, if you do so you have to take the whole time-consuming package of other classes that you may or may not be interested in, the class could be another year. Usually you do it because of pressure or you have to take the chance that the credentials are useful for something.
There are specific exceptions, one that I know is foreign language. I know people who've been 4 years on foreign language courses and haven't learned it. I suggest reading an actual book written in that language then looking up what you don't know. I know this works because I tried it, not that taking one semester of class first isn't good. But nope, maybe another class is better. Hmmm.
In my experience, foreign language classes taught by native speakers of that language tend to work for everyone. The other kind, not so much. Reading books and watching movies in class is also indispensable, all good classes do it.
LW has a problem. Openly or covertly, many posts here promote the idea that a rational person ought to be able to self-improve on their own. Some of it comes from Eliezer's refusal to attend college (and Luke dropping out of his bachelors, etc). Some of it comes from our concept of rationality, that all agents can be approximated as perfect utility maximizers with a bunch of nonessential bugs. Some of it is due to our psychological makeup and introversion. Some of it comes from trying to tackle hard problems that aren't well understood anywhere else. And some of it is just the plain old meme of heroism and forging your own way.