Writing begins with awareness of the single word, then moves up.
What can a word mean, and what does it actually mean in its current context? Does the sentence make its point as clearly as possible? Does the paragraph come together as a single point? Is it in the right place Does the whole document tell a story from beginning to end? Where does it fit within the rest of the document set?
Always know, without a doubt: What is the document’s bottom line? What is the reader supposed to learn from it? And if you can’t draw a straight arrow from every word, sentence and paragraph to that bottom line – rewrite.