
Katie I. answered 03/30/19
Master's degree in English Education, 4+ years of teaching experience
Great question. It can be hard to know when to stop. No one is going to write a story and then have absolutely nothing to change or only grammatical or spelling errors; there will be sentences that don't quite make sense, words that stand out because they're not quite the right one or stand out from the rest of the story's language, phrases that are unnecessarily repeated, etc. Typically, when I read through a story, either as a writer or merely as its reader, there are parts that will twinge your ears, like listening to a song played on a violin and having an occasional note played slightly off-key. That note may be small and last only a second, but it matters and lends to your impression of the overall quality of the performance. Misspellings can be an off-note; if a character says something that seems weird or out of character or unrealistic (the cowboy entered and said, "Howdy, y'all,"); if not-quite-the-right-word is used, maybe an overly flowery one ("It was a beautiful azure sky") or archaic one ("She donned her favorite scarf that day") -- all of these pull the reader from the flow of a story. Super long, meandering sentences, too, can lose a reader.
In short, the parts of a story that need to be revised are those that draw the reader out of the story. If you're reading your piece out loud to yourself, check for parts you stumble over -- Is there a not-quite-right word there? Is that sentence too long, and might it need to be broken up? Is it unclear who that "he" is referring to? Is "torrential" the right word to describe the rain, or is that too exaggerated?
When a story readers clearly, you'll be able to hear it, the same way that a violin's piece ends, and you say, "That was perfect."