Verlyn Klinkenborg in Literary Hub:
Here, in short, is what I want to tell you.
Know what each sentence says,
What it doesn’t say,
And what it implies.
Of these, the hardest is knowing what each sentence actually says.
At first, it will help to make short sentences,
Short enough to feel the variations in length.
Leave space between them for the things that words can’t really say.
Pay attention to rhythm, first and last.