One of them is: Sometimes, if I catch one of my characters telling another character about something dramatic that happened, I have to delete that scene and actually write the scene WHERE THE THING HAPPENED! I learned it again last week when I wrote a little scene where one cowboy tells another that some fence has been cut. But where was the action? Where was the emotion? T'warn't none. So I deleted all that and wrote the scene in which the cut fence is actually discovered by the woman who lives on the ranch . MUCH better. There's surprise happening right there in the moment, and there's the emotion of first-person experience instead of the second-person telling a third person. And because there's true action in that scene, it leads naturally to action and emotion in the next scene.
Sometimes characters have to tell each other things; you can't literally *show* everything, but whenever there's a choice, readers want showing, not telling. And I'll tell you a secret: you're not really a fiction writer untill you can write those scenes--the ones where things happen-- as they happen.
Dear Nancy, Show, don't tell. Duh. Yours truly, Nancy.