The Internet Review of Science Fiction has published this wonderful article by Jay Lake and Ruth Nestvold. It says everything I've ever tried to convince writers about writing without stopping to edit, all nicely wrapped up in an article -- with a list of ways to silence that nasty internal editor.
Here's another exercise to unlock your unconscious and stifle that editor, taught to me by a very good friend:
Sit down at your computer or blank sheet of paper and write anything and everything that comes to mind. It's called 'free writing', similar to free association. Just let your mind wander and let your fingers follow it. The result will be nonsense, garbage -- but that's okay. That's what you're going for. I think part of mine went something like 'fall down no wold too far' or some such garbage. Do that until you are firmly inside your mind -- fifteen minutes is probably a good target, if you need one.
Once that is out of your system, get another blank page and start to write. Just write. It can be your current work in progress or something completely different.
Many people who tried this exercise were completely amazed -- all that style they were trying so hard to consciously develop just flowed onto the page.
That's the power of your subconscious. Gag that infernal editor and throw him in the basement, only letting him out for revisions and edits. After all, who's in charge here -- you or him? Don't let him stifle your creativity. Make him work for *you*.