MyBirdIsEvil - I know that sometimes it's better to just start writing... but I feel as though I cannot simply write before I know the exact outline/characters. To me, writing is very similar to building a house: you have to have all of the engineering/architecture/plans done first and only then you can start building it. If you just start building, the end result may not be all that glamorous because proper calculations were not done. But then again, I'm sure that some unconventional writers also write without first having the "skeleton" down.
You don't have to use what you just started writing. Like I said, it could be something really inane and you can even discard it afterward. But it will get your mind flowing and then you can start writing an outline.
It's a common thing in creative writing classes to write journal entries and quick stories and such just to get your mind working and get used to writing in general.
Writing takes LOTS of practice, so just starting on an outline when you haven't been writing much in the first place often doesn't work for a lot of people.
Believe me, if you just sit there thinking it will never get done. You have to put pen to paper and just do it.