Before you write about a subject, make sure you know it inside and out. If there are questions in your mind, don't skip them or cover them up. Do your best to find the answers. Then, if questions remain, you can always be honest and say so; the reader will forgive you.
Whenever there's something wrong with your writing, suspect that there's something wrong with your thinking. Perhaps your writing is unclear because your ideas are unclear. Think, read, learn some more.
The old admonition to "write about what you know" is a cliche, but it's still good advice. No matter how vivid and fertile your imagination, you'll write best what you know best.
Patricia T. O'Conner, Words Fail Me, 1999