Billy Wilder’s tips for screenwriters.
Most of them also apply to novelists. The only one that could be debated is #10:
10. The third act must build, build, build in tempo and action until the last event, and then – that’s it. Don’t hang around.
But that’s because movies are more like short stories, or at most novellas, than they are like novels. That’s why Tolkien’s extended fourfold wrap-up of The Lord of the Rings works in the context of the novel, but is less effective on the big screen.
(Also, of course, it is necessary to remember that in a perfect world any writer’s advice on writing would come with a clearly-printed THIS IS HOW IT WORKS FOR ME, ANYHOW label attached.)