Writing is related to character. If your values are sound, your writing will be sound. It all begins with intention. Figure out what you want to do and how you want to do it, and work your way with humanity and integrity to the completed article.From On Writing Well: The Classic Guide to Writing Nonfiction by William Zinsser.
I recommend books on writing about as often as I read books on writing--which is to say never.
Though it has been many years since I graduated from college, I still can't quite believe my luck in having studied writing (and literature) with the greatest of teachers: Marvin Mudrick. Nowhere to go after him.
But I couldn't and didn't--though I wish I could have--memorize every word he said about literature and writing. Hence the utility and pleasure of a book like On Writing Well. It is truly a pleasure to read. How many manuals or guides can you say that about?
If you are a writer and you haven't read it, do. You'll be so glad you did. If you know everything Zinsser tells you, you'll feel gratified; if you learn something new, you'll profit from it.