I use the canned air as well, and definitely at an angle. I have a lens that has dust on the INSIDE elements. It used to be a minor annoyance, but has become a huge problem as it has gotten much worse. That is one of the hazards of aviation photography, especially when C-17s are taking off at Riverside!
I was out at Santa Paula airport today and the wind was howling through their, the worst I have ever seen it there. When I left after just a couple of hours, the gear was really dusty.
Canned air, and lint free clothes are good starts. You can wet clean the sensor, but you have to be completely comfortable with that kind of thing before attempting it.