If you're like every other author in the history of the written word, you sometimes have trouble getting the ball rolling on your short story ideas. This is where writing prompts can come in handy. These are various techniques designed to get you sitting down writing without having to come up with the intial idea. The idea behind a writing prompt is that once you get going, the story will create itself.
One way to get a story going is to select three elements for your tale. You might wish to create flash cards with a number of story elements -- conjoined twins, a missing diamond, an overbearing boss, a loose tooth, a love letter, the first day at a new school or anything else you can think of -- and select three at random.
You could also begin with very basic dramatic situations based around stock characters to get the ball rolling. Examples of this include a man reading an all-too-accurate fortune cookie, a woman telling her traditionalist parents that she plans to divorce, a man handing a woman a mysterious package on a subway platform or the loss of a job in a tough economy.
You can also use a challenge to yourself as a writer as your writing prompt. For example you could challenge yourself to make a list of your five biggest fears. These can then all happen to your character. Name your worst habit. Now imagine a character who has the same problem but much worse. Alternately, select your greatest personal asset. Now imagine a situation where a person needs this attribute but doesn't have it.
Write a list of exciting but unrelated sentences and keep them on hand. Pull them out when you get stuck. What you brainstorm will be far better than "It was a dark and stormy night…" or "once upon a time..." When one prompt doesn't work for you, try another until you get the prompt that is right for you.
William S. Burroughs was fond of an exercise where you write as another author for a month. You can use as much or as little of the author's writing as you like, but the important part is to emulate her style. Spend some time reading the great works of literature, such as Jane Austen, John Dos Passos or Joan Didion. Now copy that style. Select a new author every month.
If you're seriously stuck for a short story writing prompt, ask friends in your book or writing club. They are sure to have plenty of ideas you can use in your next short story.
Writing prompts don't need to be used to write entire novels or even stories. You can use a number of them in succession to get your creative juices flowing. One way to do this is to find a list of someone else's prompts and do short "flash fiction" stories about each. These are works of microfiction that are often no more than page-long thumbnail sketches.
Writing prompts are useful tools for when you're sitting at your keyboard staring blankly into space, at loss for the start of a short story. Prompts will help you achieve your goal of writing daily. Best of all, most prompts are available free of charge. Even if you find that you don't write anything that you can keep using the prompt, you might find material in the writing that you want to spin off into a full story. Whenever you use a prompt that works for you make sure to accumulate good writer's karma and give back to the community by coming up with a few prompts of your own.This is true whether you are writing genre fiction such as a mystery story or more literary work.