I think many if not most here will agree that the really important rule is that rules can be broken. Rules can be broken, you just have to be good enough to carry it off. Every rule they give you about writing can be broken in a certain situation.
That said, the rules define craftsmanship and excellence. So learn the rules, use them, and youll then be able to break them to good effect.
Thus, showing is better than telling, usually. But not always.
Present tense is better than past tense, usually. But not always.
Blah blah blah, she said is better than Blah blah blah, she breathed, usually. And so on.
The secret is that you have to be good enough to carry it off.
Fast forward almost thirty years to a fourteen year I knew who almost threw the book down because of the background. Where was the action? Why was this included? Was it necessary?
Probably not. But when I asked her what the rush was she said that she just didn't see the need for this "stuff".
I got to participate in a fascinating discussion on whether books are dying out because of TV, movies, and things like graphic comics. That the thought of sitting down with a book on a rainy afternoon was becoming a think of the past and soon...books would go the way of the horse and buggy. People do not want to invest the time and energy of reading a book.
I said I do not believe so because people will always need heros, but of the 15 people in the room, I was the only one who thought the "novel" was not on the endangered species list.