Decide on the premise for your story. A short story needs to be about something. The main character of your story must have a goal. Where does he want to go? What does he want to do? The thing that is driving your main character is your premise.
Choose a point of view. Are you writing in the first person or as a third-person narrator? A third-person narrator writes as if watching what is happening in the story. The first person is when the main character is telling the story.
Show who your main character is by his actions and dialog. Your audience must care about the character and his goals. As your character is moving through your story, the reader should discover who the character is by how he reacts to the situations presented to him.
The plot is what happens in your story and the order in which the events occur. Outlining is a practical way to plot out your story. An outline will help you to see how the action in your story flows. Your plot must move forward in chronological order to avoid confusing your reader.
Adding conflict to the story will help pull your reader into the story. Conflict lies at the heart of all fiction, whether it is character vs. character, character vs. nature or character vs. himself. Something has to happen to the main character or to someone he cares about that causes him to want to reach his goal. This is your conflict.
The goals of your main character should accumulate toward the story's climax. The climax is the point in your short story where the main character has to act or lose everything. He has to save the day, make the right choice or rescue a loved one. The climax is the most emotional point in your story.
Your story should offer a complete resolution to the goals and conflicts in the story. Tie up all the lose ends so your reader feels satisfied that all the issues brought up in the story have been resolved.