On those days when you don't have anything lined up to photograph, it is a good idea to work on your slow shutter speed hand-holding ability. It is a matter of strength training, and with practice, you can greatly improve your abilities. I was able to get this shot at a pretty slow speed, although I was sitting down, which makes it easier. I shoot about half the time with a much heavier camera, so that has helped a lot with my abilities with the D90. Practicing in advance will give you the skills when you need them!