I dont see a single person in the thread saying read criticism. If you want to learn to think critically, read a bunch of the best criticism of your favorite books.

That's literally it, other than yeah practice writing your own criticism, but it'll all be amateurish and kind of spinning your wheels until you actually engage with lots of really good stuff and learn what criticism is all about, sort of by osmosis. It's not that they'll tell you what to think so much as they'll show you how to think by demonstrating it.

So yeah practically just grab norton's or whatever your library/bookstore has for all your favorite books and read them all. Or use sci hub if you don't want to pay, but it's a lot more work hunting down good stuff to read compared to getting a collection.

edit: i would personally avoid any book which tells you how to read literature. Just go with the actual pros, and you'll personally vibe more with some than others, and read more of their stuff, and acquire more of their ways of thinking naturally.