Just write something already...

The scariest thing about doing something for the first time is actually doing it.  Once you've done it, it shouldn't be as scary.  You've survived, theoretically speaking.  You've taken your first steps - jumped off the high diving board at the pool - asked the girl to dance - moved to a new and unfamiliar city.  You may have thought you would never have the guts to do it, but you did it.  And you're still here.  Surprised?  You have already accomplished so much!  Remember your baby steps?  It's time to take bigger ones now.