Answer by Romi Ezzo:
Blinkist (one of my favorite apps) recently wrote aabout this.
The author came up with a 7-step process (based on scientific studies):
1) Find a personal angle: You need to relate to what you’re reading
2) Get a bird’s eye view: Get the basic outline of the book by skimming through the table of contents (and the rest of the book); try finding a central theme
3) Drum up curiosity: Draft a few “curiosity questions” based on the theme; consider these questions as you read the book
4) Create your own structure: Identify key points in the book and leave space for you to take in-depth notes
5) Record key insights: Take in-depth notes based on the elements you mentioned in Step 4; think about what the “Takeaway Message” is.
6) Review your notes: Now that you have a summary you have created in your own words, it’s now time to review; try to remember the details related to the messages you recorded 10 minutes, 2 days, 1 week after finishing the book.
7) Repeat with another book.
(The seventh step is one that I added, since they had a typo in their blog.)