For non-fiction book reading, Shane Parrish recommends that you

• Learn How to Read A Book.
• Start with the index, table of contents, and the preface. This will give you a good sense of the book.
• Be ok with deciding now is not the time to read the book.
• Read one book at a time.
• Put it down if you lose interest.
• Mark up the book while reading it. Questions. Thoughts. And, more importantly, connections to other ideas.
• At the end of each chapter, without looking back, write some notes on the main points/arguments/take-aways. Then look back through the chapter and put anything down you missed.
• Specifically note anything that was in the chapter that you can apply somewhere else.
• When you’re done the book, take out a blank sheet of paper and explain the core ideas/arguments of the book to yourself. Where you have problems, go back and review your notes. This is the Feynman Technique.
• Put the book down for a week.
• Pick the book back up, re-read all of your notes/highlights/marginalia/etc. Time is a good filter – what’s still important? Note this in the inside of the cover with a reference to the page number.
• Put the notes that you want to keep in your common place book/resource.

Writing while you read -- highlights and notes -- seems to be key.