Now's the time to begin work on something BIG! Don't worry if it is not perfect. Follow Snow's advice and get the story started; perhaps start with an interesting character in some difficult situation. Like Catherine said, look to life for ideas.
Try to have something here before next class. I will too!
14 Tips for Writing the Short Short Story (some pretty good advice; scroll down to read)
Anton Chekhov's Short Stories (often very short so are good models to follow)
Short Stories: 10 Tips for Novice Creative Writers