King on Writing Successfully
Stephen King's On Writing is fantastic, and if art/act of writing interests you, it's something you should seek out.
Aside from that though, there's a famous short version that he wrote a while ago that usually is available in the annual Writer's Market, called "Everything You Need to Know About Writing Successfully - in Ten Minutes."
Since the original includes graphics that show how the editor edited his text way back in the day, I've never attempted to re-create it for the web. Well, somebody did if for me (us), but without the graphics.
Check it out.