Start off your outline by dividing it into three sections; the beginning or introduction, the middle and the end. You can also label these Act I, Act II and Act III.
Create three subheadings for each heading. Under the first primary heading, or introduction, you want your three subheadings to be: characters, setting and main character's problem. Under your second heading, label your subheadings: dealing with problem, outcome of dealing with problem and character's change or moment of realization. Under the third heading, your subheadings consist of: climax, resolution and conclusion.
Determine the subheadings of the Introduction by thinking about your character, where the action takes place for him and what kind of problem could really turn his life upside down. The problem stems from his own insecurities or issues. For example, if he has a fear of death, perhaps he's confronted by the grim reaper itself. The introductory stage of the outline should show little notes that introduce the character and the main action of the story.
Develop the second act, or middle of the story, by determining how the character deals with the problem, whether she fails or succeeds (typically she fails) and what realization this failure or success brings to her. Basically in the subheadings you want to detail simple plot points that lead the readers to discover more about both the external, physical journey of the character as well as the internal, emotional journey.
Lay out the final moments of the short story with your final heading. You want to detail the climax, when the hero of the story has to battle with the problem he faces more than he ever has previously. You also want to note the resolution of this battle and conclude how the overall experience has changed the main character, as well as the world around him, if applicable.