If proper usage gets in the way, it may have to go. I can't allow what we learned in English composition to disrupt the sound and rhythm of the narrative. -- Elmore Leonard
I like the sentiment in that quote from Elmore Leonard about the “sound and rhythm of the narrative,” because those two things help propel a story. That’s why I recommend to my editing clients that they read their work out loud, either to someone they trust or to themselves. Not only will reading out loud help you spot small errors, like sentences that are missing a word and other typos, but it will also help you discover where the rhythms of a phrase or a sentence or a paragraph are awkward. If you’re stumbling over your words when you’re reading out loud, look carefully at the passage. Sometimes the reason a sentence sounds awkward is not a matter of grammar or sentence structure but a matter of sound and rhythm.
Contrary to Elmore Leonard’s feelings about “proper usage,” however, I still believe it’s important, particularly in the final steps of polishing your story. The goal is both grammatically correct sentences and flowing sound and rhythm, and the solution to either problem—incorrect grammar or the disruption of the sound and rhythm of the narrative—is to simply rework the sentence.