> Another secret is to not be scared of quitting a book. I definitely start way more than I finish. But I don’t consider an uncompleted book a failure or a bad book. I think that sometimes books have a certain time to be fully appreciated. So if I don’t finish a book today, I might try reading it again in the future.

Well said. On a related note, I think the idea of coming back to books later is essential to reading non-fiction, as I've personally found it much more productive to read until I think I've "got it", and then revisit it a few months later with a new (ideally better informed) perspective.