Nancy Pearl’s Rule of 50 for dropping a bad book
What has worked really well for me has been to follow Peter Bregman's reading technique, which he got from history professor Michael Jimenez (story and full article here: https://hbr.org/2016/02/how-to-read-a-book-a-week):  1. Check out the author’s bio online to get a sense of the person’s bias and perspective. 
  2. Read the title, subtitle, front flap, table of contents. Figure out the big-picture argument of the book, and how that argument is laid out.  
  3. Read the introduction and conclusion word for word to figure out where the author starts from and where he eventually gets to.  
  4. Read/skim each chapter: Read the title, the first few paragraphs or the first few pages of the chapter to figure out how the author is using the chapter and where it fits into the argument of the whole book. Then skim through headings and subheadings to get an idea of the flow. Read the first sentence and last sentence of each paragraph. Once you get an argument, feel free to move on to the next argument, skipping over the many repeated case studies or examples.  
  5. End with the table of contents again, looking through, and summarising each.

I've found that this has worked wonders for my reading. A year or so later, I refined this technique further, as I found that it didn't work for all books (it works for 'single-idea' books, which I call 'branch books'; it doesn't work as well for 'map of ideas' books, which I call 'tree books'.) For example, The Long Tail is the an example of a branch book, and Thinking: Fast and Slow is an example of a tree book.(I've written a longer post about the categories here: https://commoncog.com/blog/the-3-kinds-of-non-fiction-book/)Edited for formatting