When I read How To Read a Book, I was quite impressed. In practice ... it's not very useful for the types of book I read. Likely better for deeper, philosophical books (including fiction of that category).
For a lot of fiction books, my rule is to read the first 50 pages. If I'm not engaged, move on. Life is short. I believe Stephen King also used that heuristic. It's fine if you miss out on some great books. You're not going to get to read all of them anyway.