In theory, there are ways to make time travel work, but it’s hard to make it interesting. I don’t think I’ve read any time travel book other than Well’s.
What book did you particularly enjoy because of its following of its own rules? And the opposite: a book that doesn’t hold up to this standard?
I’m currently reading The Moor’s Last Sigh by Rushdie. His narrators tend to be wacky and his characters often do unconventional things, but when you read these books, you never feel like someone did something out of character. You read something outrageous and still feel like the character would definitely have done or said that.
Characters that are written consistently, so that if they do something that is 'out there' later down in the story, the writing would have shown before hand how they got to that place.
To me, variety in characters is oddly important. By this, I don’t mean a superficial diversity, even if that helps, but more on the emotional level. If all the characters are smart and outgoing, or introverted and shy that doesn’t make for an interesting read in my opinion.
I think different readers enjoy different things in a book. Reasons for why a person may like a book may vary from individual to individual. For me, the most important reason for liking a book would depend on how real the characters feel to me and how much emotionally involved I feel with the characters. If a book fails to make me care for the characters, I lose interest. It's even better if the book has philosophical undertones. Additionally, prose also matters. So, I can't give an opinion on what makes a good book; I can only speak for what I like. And if I fail to get interested in a book beyond ~25-30% mark, I DNF because life is short and I would rather read for pleasure. For me world-building is not important, however someone who loves world-building over everything else might love a book which someone like me may not like at all. So books of different styles are great for different people who would enjoy them.