Elmore Leonard
Much is made of Elmore Leonard's 10 Rules for Writing. Not so much is made of them by Elmore Leonard, but others have gotten a lot of mileage out of them. And they aren't wrong, and they are obviously distilled from Leonard's own writing.
Much more should be made of Elmore Leonard's actual writing. At this point, gentle reader, I know you have said to yourself "Duh, John" or some kind of "tell me something I don't know" equivalent. However, do not dismiss the actual wonder that is the writing of Elmore Leonard and is completely absent from simple rules, no matter how useful they are.
Toward the beginning of Cuba Libre, Ben Tyler shoots an Spanish officer who draws a dueling pistol on him in a crowded bar. The build up is pure Leonard: nothing sounds like writing. You don't skip over any of it. It's all told from the point of view of an American reporter, who alternates between conveying the narrative and editing it for publication in his own mind. The genius is in the line just after Tyler kills the Spanish officer.
My lord. The sound it made.
That line right there makes everything that comes before it that much more real, and gives credibility to every description that comes after it. It's an aside. A figure of speech. And yet it is the key to this whole passage, one that has so captured my attention that I am writing a blog post about months after I last wrote, and I am doing so a full ten days after I read the line.
Seriously. If you want to know how to write, skip Leonard's rules. Just read his books.

