After lending me his camera enough times for me to realize that some of my dissatisfaction with my pictures WAS the camera, Peter just bit the bullet and bought me a housing and strobe. I've tried a couple of dives with it (enough to finally figure out that if you set the strobe on "Auto", it doesn't fire) and today's dive was totally for the purpose of taking a lot of pictures and trying to figure out what I was doing.
Peter still set the camera up for me; it was aperture priority today at f10. I really liked the way that gave me lit subjects and dark backgrounds. I played around for a long time, trying to get a picture of a metridium that I liked, and gave up, and went back to small things.
I think it's getting better.