When this becomes habitual, the actual teach-ing of style is over.
This is what I'd consider the "end game" to learning grammar style. Before learning style, a writer would think through their ideas and the structures of their sentences based off of what sounds the best to the reader. It turns out that what sentence structure sounds best to the reader is not something unexplainable, but is something one can learn and study. After learning grammar style it is much easier to structure sentences properly or find out what is wrong with a sentence (double clauses, run-ons).