Snoopy has it right--beginnings are sometimes the most difficult part of the story. As a former SOTP (seat-of-the-pants) writer--(no plan, just sit down and write), I can totally relate. It has taken me three years to learn that an outline, however brief, is a great help to mapping a story. Sometimes I only know the beginning and the end and have to do some thinking about the middle, but I try to get it figured out before I actually start the story. However, winging it from the start can lead to some interesting twists in the storyline, LOL!
What about you? Do you make an outline for your idea, or just let the story evolve as you write?