Editing is a separate job

Writing and editing use different attention and doing them at once produces slow, timid prose. Draft badly and quickly, then leave it — overnight if the deadline allows, twenty minutes if it does not — and edit as though someone else wrote it.

On the edit, cut ten percent. Not because ten percent is magic, but because a firm quota forces you to find the padding, and there is always padding. Then read it aloud; the ear catches what the eye forgives.