Answer the "what" of your story. Read or reread a few stories, brainstorm, then write the premise of the story in one sentence. The premise could be as simple as answering the question, "What would happen if . . ." Next, determine the genre of the story. Decide whether it is literary fiction, a mystery, a romance, a thriller, inspirational, an adventure, or a western.
Answer the "who" of your story. Characters include a protagonist, an antagonist and supporting cast. The number of characters is often dependent on the length of the story. Whether it's a short story with two or three characters or a book-length story with many more, only include characters integral to the plot. Create a storyboard that traces the inner and outer stories and desires and goals of each character. How do they mesh or conflict? Once you track the arc of the characters' stories and desires, your plot is underway.
Answer the "when" of your story. Determine the time period when the story takes place. It's crucial to show how the time period is reflected in the attitudes and agendas of the characters involved in the story. Make sure you clearly show the passage of time. Capture the prevailing cultural attitude and how it ties in with the plot.
Answer the "where" of your story. The setting and location work almost like another character in the story. Engage the senses. Go beyond the visual and capture how the setting sounds, how it smells, how the air feels. Is it a sunny, peaceful, playful time taken for granted, like the Hobbits in the Shire? Or is it a dark, gritty, fearful, urban mystery noir setting, smelling of rain and ozone?
Answer the "how" of your story. This is the heart of the plot. The protagonist, for example, may experiences a call to adventure or some other type of challenge. As the stakes get higher, deeper secrets and truths are revealed. This becomes the climax of the story.
Answer the "why" of the story. Whether or not the protagonist or antagonist is the winner, there is a reward. Each of the characters should have learned a truth about themselves and been transformed from what they've faced.