Very simply, this is one of the best articles we’ve seen on revision.
Revision requires you to recognize a gap between what you intended and what you achieved. Closing that gap is pretty much the definition of revision. But if you recognized that gap initially, you wouldn’t have made the mistake, so I call these gaps “blind spots.” Blind spots are different than grammatical ignorance or oversight (such as using a colon wrong). Blind spots are things like weaving in a sub-plot that powers an entire character arc but that actually doesn’t exist on the page–only in your head.
My biggest personal blind spot is not being clear enough in outlining character motivation. Critique partners will often say, “I don’t understand why that happened” or “I don’t know why she did that.” Thus one of the first things I do in revision is go through and make sure all the pieces of the narrative are clearly communicated. It’s so basic, but it is something I miss all the time.