Also, caveats. If I had to come up with this list in August of 2008, right after Clarion was finished, it would have been different than it is today. Ask me again in a year, three, five, and my guess is the list will have changed once more. I learned a lot when I was there, but the things that are most important to me (both in terms of writing and in life) have changed, and will again.
1. Write ten endings. Since the meme is at Jim's request, we'll start with one I learned from him as part of "Jim Kelly's 10 Stupid Plot Tricks." I use this all the time, not just - and not usually - for the ends of stories, but for the what happens next. A useful corollary to this, a 1a., if you will, is Neil Gaiman's suggestion that, when you don't know what happens next, ask your character what she wants.
2. Eventually, you have to walk down the street naked. Neil again. Terri Windling and Ellen Kushner (another Clarion instructor, though not one of mine) have written about this recently as well. In other words, be brave enough to write your story. Stop worrying that your mother, or your priest, or your lover will read it and decide you are a pervert or a freak. Pick up your pen, and write your story.
3. There's very little that can't be fixed by a watergun battle, an all-night dance party, or a Buffy singalong. Some days, being a writer sucks. You mix your metaphors, dangle your participles, and split your infinitives. The first thing you see in your inbox is a rejection letter. The critique session makes you cry. Remember that there is life outside of writing, and live it.
4. You can be a good writer without putting yourself on the page. You can't be a great one.
5. Writing is a job. Show up for work. When I taught this fall, three of my writer friends came in an guest-lectured for me. Every one of them was asked how they deal with writer's block. Every one of them answered: "Writing is my job. I don't get to have writer's block." If you're going to be a writer, in the words of John Scalzi (teaching at Clarion this year), "find the time or don't." Don't wait until your life is awesome, or the muse visits, all smiles and seductions, or until you know what happens next. Put your butt in the chair, and write.