One more suggestion that helps me (I got it from this board!) is to turn the wheel the opposite direction of your unclipping foot - this will make the bike lean toward that foot. So I always unclip my right, and turn the wheel a bit to the left as I stop.

Knock on wood, I have not fallen yet (give it time, I'm new and I know it will happen), but the closest I have come was when I did not turn the wheel, and the bike started to lean to the left and of course that foot was still clipped in! Thankfully, because my tension is set so low, I was able to yank my foot out in time!

Trish