About 20 years ago I started keeping track of the books I read in a book journal, usually a 5x7 hardcover lined notebook. It wasn’t a particularly elegant system - I simply listed the title and author of the book, using a separate page for each month. If the book was a particular favorite, I might jot an asterisk beside it; if it was the second (or third or fourth!) time I’d read it, I would note that too. At the end of each month, I totaled the number of books read during that time, and at the end of the year, I skimmed through the year’s reading and made a “favorites” list.