One technique I've used is to simply copy somebody else's story, word for word, typing it out. When I'm done, I start thinking of the different ways that story could have been told, and what might have happened along the way that would have made it a different story.
Then I write the story the way I would have wanted it to be, having had the characters in my head long enough to tell me their perspectives.
Lastly, I go back and change all the names to cover my tracks.
