One thing that often stops people from writing is not knowing exactly what they want to say. Many people figure that "good" writers know where the story is going, what point they want to make. They figure "good" writers fully understand their position before they start writing it down.

That's almost never true, and the few authors that say they do know everything I bet are lying.

Writing is thinking1. The act of putting pen to paper, or fingers to keyboard, helps you sort out what you think about a subject. The act of doing a bit more research introduces you to new ideas that may change your opinion.

If you think you have something to say, go sit down and start writing about it. When you get something down, stop and think about the questions people will ask about your writing. Then do some more research and write down the answers to those hypothetical questions.

You won't know what you think until you start writing.