Andrew Wheeler writes about how his old job at the SFBC taught him how to review books:
I started off in “book reviewing” by writing internal book reports for the SFBC; I did six of them my first week at the club, back in April of 1991. I was very eager, and incredibly willing to read almost anything my boss put in front of me — I recognize that same eagerness and enthusiasm in a lot of young bloggers now, and wince to remember when I was like that. I was lucky in two ways: those reports had a clear structure (one phrase to define a book in genre and style, several paragraphs of plot description, and then a short personal evaluation at the end), and they were internal; no one outside the company ever read them.
I wrote hundreds of those over the next few years, learning to boil down complicated plots to their essences, to take good notes on books as I read them, to keep track of characters, and lots of other mechanical skills. More importantly, I learned to read actively, to think about a book as I was reading it and to start making hypotheses and guesses about the shape and course of a book while in the middle of it. That’s one of the core necessities for a critic of any kind: you need to engage with the work directly, to think about where it seems to be going (rather than where you want it to go, or where it does eventually go) and get a sense for the shape of those works.
That actively reading of a book, to read it with one eye on what you’re going to write about it is the essence of critical reading. You’re not just looking at the story itself, but also at why the author might have made the choices they made in telling the story, or at the deep structures of the plot and how the need to end the story in another hunderd pages or so limits what can happen now. It’s the same for non-fiction, where you’re looking at how the author structures their arguments and how you’ll be able to quickly summarise the key points of it in your review later. It does sort of inhibits your ability to lose yourself in a book…