More from William Zinsser. This time on paragraphs:
Keep your paragraphs short. Writing is visual -- it catches the eye before it has a chance to catch the brain. Short paragraphs put air around what you write and make it look inviting, whereas a big chunk of uninterrupted type can discourage a reader from even starting to read.1
Paragraphing is a subtle but important element in writing nonfiction articles and books, a road map constantly telling your reader how you have organized your ideas. Study good nonfiction writers to see how they do it. You'll find that most of them think in paragraph units, not sentence units. Each paragraph has its own integrity of content and is rounded off to serve as both an end and a springboard to what's coming next.2
1. On Writing Well. 5/ed, New York: Harper Collins College Publishers, 1995, p. 126.
2. ibid. p. 128