After thirty years of teaching a university course in something called advanced prose style, my accumulated wisdom on the subject, inspissated into a single thought, is that writing cannot be taught, though it can be learned—and that, friends, is the sound of one hand clapping.
I don't have an opinion of Fish's book or Epstein's review of it. I just really like that way of putting it.
So why do I bother trying to teach it? Because you can actually help someone learn if they are willing to put in the effort. At bottom, piano playing or skating or drawing can't be taught either, but someone who has learned how to do it can help someone who does not yet know how (but really wants to) figure it out. It's all in the figuring-it-out-by-yourself. Read other people and try to work out how they did it. And practice.
If you just want to write, you probably already know how. If you want to know how to write well you've got some work to do. And only you can do that work.
There are lots of tricks, but they are not tricks to writing. They are things like: first, clarify the key sentence in the paragraph, then write the paragraph three different ways. Or: make the five key sentences in a section of your paper so clear that you can memorize them and when you tell them to someone else only once they can give you the gist of the section back.
The knowledge you lack will be acquired simply by writing. There is no other way.