Master storyteller Kurt Vonnegut once gave a talk in which he discussed the different shapes stories can have; it's funny. Here is the video.
The video is only a portion of Vonnegut's talk but this transcript gives the entire thing.
Since we're talking about Kurt Vonnegut and writing, here are his rules for writing:
1. Use the time of a total stranger in such a way that he or she will not feel the time was wasted.
2. Give the reader at least one character he or she can root for.
3. Every character should want something, even if it is only a glass of water.
4. Every sentence must do one of two things —- reveal character or advance the action.
5. Start as close to the end as possible.
6. Be a Sadist. No matter how sweet and innocent your leading characters, make awful things happen to them -- in order that the reader may see what they are made of.
7. Write to please just one person. If you open a window and make love to the world, so to speak, your story will get pneumonia.
8. Give your readers as much information as possible as soon as possible. To hell with suspense. Readers should have such complete understanding of what is going on, where and why, that they could finish the story themselves, should cockroaches eat the last few pages.
Kurt Vonnegut goes on to say:
The greatest American short story writer of my generation was Flannery O'Connor (1925 - 1964). She broke practically every one of my rules but the first. Great writers tend to do that.
I would give you a link to where I got these rules but I printed them out years ago and keep them the sheet tacked above my writing desk.