What's your method of composing?

How do you get what’s in your head onto paper? Mozart, for example, got everything perfectly organized and edited in his head, then wrote it all down on paper into a final copy. Others play around with the piano before finding something satisfactory, then try to write down that as best as possible. I usually write it down on the computer, then edit and re-edit as needed. How do all the other composers here do their work?