1. Good grammar. Already discussed. And Jerry, SPOT ON about adjectives.
2. Good flow. Already discussed. But spice it up every once in a while.
3. No cliches (unless trying to be cheesy). Next.
4. No long paragraphs of unnecessary description. Being bored to sleep is NOT a goal in writing.
5. Albert Camus' L'Etranger is NOT good writing, in either English or French. *shudders*
6. Minimal or no plot holes. Minimal or no holes in arguments.
7. If you can read the last few pages of a novel and have a good idea about the story as a whole, it is likely bad writing.
8. Be concise, be brief, don't use big words just for using big words.
9. Repetition is good. But don't overwhelm the reader with it (ie. No Great Mischief). Then it is just annoyance and page filler.
10. Consistency in style (unless TRYING to call the reader to something. Know the rules before you break 'em).
11. Proper quotations... PLEASE!

I'd rant some more, but thinking about this stuff makes my brain want to beat its way out of my skull.