Zinsser's On Writing Well
The topic of writing guides came up today, specifically books that help with style and the craft of writing, and I remembered this book from my journalism classes. Google revealed a few good links related to it: an excerpt from an early edition and an article from last spring telling the story of the book and all its various revisions
The book is full of excellent advice. It's geared toward nonfiction writing, but its lessons apply to fiction as well, especially to writing short fiction where being concise is key. Many fantasy writers suffer from word bloat, and this book is an essential weapon against that. As I mentioned to the person asking for advice on writing guides, after absorbing the advice of this book, you may still choose to write flowery sentences, but those flowers will have stems made of steel and will serve a genuine purpose, not just to make you look smart (or to fail at making you look smart, as the excerpt argues).
I took that journalism class back in 1997 or 1998. I've skimmed the book since then, but after reading the excerpts, I can see that I ought to read it in full once more, and the article on the various editions makes me want to check out the newest one when I do. I recommend you do too.