See, when I tried to do that, I inevitably start editing as I go with the intent of making it as final as possible. It slowed me down horribly, so now I do the complete opposite with no editing on the fly. This allows me to easily get first draft done quickly, and then I do the editing that I would have done on the fly for the first edit.
Even if the open windows of science at first make us shiver after the cozy indoor warmth of traditional humanizing myths, in the end the fresh air brings vigor, and the great spaces have a splendor of their own - Bertrand Russell