I shoot my hand as an identifier, too. Years of film shooting has me accustomed to shooting "slates". These can be very good time-savers later since they isolate groups of frames.
As others have mentioned, horizontal panos are best shot left to right, vertical panos top to bottom. I will sometimes shoot a pano right to left if the rightmost frame is time-critical and the others aren't. I'll wait for a sailboat to cross the sunpath (or whatever) in the rightmost frame, then shoot the other frames once I have that one recorded.
I believe iView Pro will sort images that are shot close together in time. ie "give me a listing of all groups of images with less than five seconds between frames" Could be useful for culling pano source images from large shoots at a later date. I've yet to try this, though.