The number one most important thing that applies to writing well is the heart. Not grammar knowledge. Not sentence structure. Not a large vocabulary. But the ability to feel real feelings fully and express them as sincerely as possible, even if you're writing satire. Is there truth within what you say? Have you painted over grey with white? Are you making honest observations or convenient ones? The truth is rarely convenient, rarely neat. A good writer is someone who can draw this mess out onto the page so that the reader can contemplate it as well and a good writer is someone who can aslo form artwork out of the mess. Something tangeable. Something the head can be tilted to, the lips exlaim, "ahhh."