OK. My brain has snapped back into writerly mode after a hiatus. So, onward with the
rules of fiction per Samuel Clemens.
10. They require that the author shall make the reader feel a deep interest in the personages of his tale and in their fate; and that he shall make the reader love the good people in the tale and hate the bad ones.
I'd modify that. A lot of us are into nuanced portrayals of good and bad, wherein outright love and outright hate of a character isn't really the key reaction. This is one thing that did really excite me about anime (and carries over into Fire Emblem)-- principled antagonists who aren't merely "bad" people. And honestly, there is some really successful fiction, like The Crying of Lot 49, wherein deep emotional investment in the characters isn't really... the point. Oedipa Maas is something of a successor to Nick Carraway, but the reader probably doesn't identify with her the way they're invited to identify with Nick. But, yes, generally speaking, a successful book is one wherein the reader takes a deep and personal interest in the characters. Harry Potter didn't get to be so popular because the magical meta was well-constructed, after all. Character love and character hate in the Potter fandom is a thing to behold... even of some of them seem to be reading Bizarro Land copies of the books.
And, in a worst-case scenario...
But the reader of the "Deerslayer" tale dislikes the good people in it, is indifferent to the others, and wishes they would all get drowned together.
I've read books like that, oh yes.
11. They require that the characters in a tale shall be so clearly defined that the reader can tell beforehand what each will do in a given emergency.
This was the rule that made me sit up and take notice. It's an awesome rule. I've held for years that the writer ought to know what their characters will do in an emergency, but that's with cheat sheets and pages of character ruminations and all kinds of background info. To have all that communicated cleanly to the reader so that they know that it's right when the by-the-book character gets flustered and the sensation-seeking screw-off buckles down under pressure, that one character copes by deliberately focusing on one static moment at a time and another processes it all on autopilot... that's impressive. That's something to aspire to, if not as a main goal than at least as some secondary or tertiary goal in the back of the brain. I like that idea. A lot.