Cheap Tricks

The idea of the "cheap trick," Dara's loving terms for a key element of stories, is one I've been thinking about all week, especially with the books being read in my school. I conferenced with a student about The Great Gatsby and we talked about the death of Myrtle as a turning point in the story. In my class, we're reading The Stranger, and there part one ends with the famous "Killing an Arab" scene. I keep thinking about how to add elements like this into my stories, and not be afraid of making things up, as Dara urged. How do other people do this? How do you come up with ideas for how to move the plot ahead?