Flash fiction: just what is it?

Flash fiction is short-form story telling.  There's no rigid definition in terms of word count (though we at BrevityThing use 250 words, flash fiction can be defined as anything up to 1000 words, depending on the publisher or website). 

Flash fiction can go under a range of other names too: short-short stories, sudden fiction, fast fiction, and micro fiction, as examples.   Very short stories (under 100 words, and sometimes the word limit is expressed in characters, rather than words) are sometimes called pico-fiction. 

The standard definition for a short story is fiction that can be read in one sitting.  But many people don't often have a spare half hour to laze in a leather-backed armchair to read long-form fiction; we have minutes grabbed on the commute, or stolen moments on the PC at work - less time.

Plus the pace of life in general is faster:  fast food, broadband internet,  multiple competing pressures for our attention, movies that are little more that quick-edit action scenes, 24-hour culture.  Flash fiction is both a reaction to, and a consequence of this.  Flash writing allows us to get in,  tell a story, and get out - all in under a page or a screen of text.

But that's not to say that flash fiction can't be exciting, compelling, vivid, touching, evocative, haunting, funny, exciting or scary, just because it's brief.  Part of the excitement of the form is to work to tight pressures and still convey an emotion and/or tell a story with resonance, and do it with economy.

So what do flash fiction stories need?  The same as short stories, or TV episodes, or short plays: 
a beginning, a middle, an end; a character, a situation, a resolution. 

And often the best way to do it is to write.  Don't worry about limitations at first, just write.  Then study the first draft and see what can be done to tighten it.  Then work on your characters.