The biggest tip/no-no Ive heard with the california duster is that you need to be 100% sure whatever you are "dusting off" has never gotten wet.
If its just pollen, dust from the air that landed on the car, etc...its fine to take off before its wet. But once its gone thru a wet/dry cycle its caked on and either wont come off or will mar the rest of the paint as you drag it off.
Optimum No Rinse is highly recommended, although Ive never used it. As bad as it sounds, the best success Ive had during our nasty Northeast winters is not washing the car at all (my car is Opti Coated so its protected even if its dirty.....to me you are better off not risking swirling it all until its warm enough to take a couple hours and do it right). Ill wash it around Thanksgiving and then once the weather is a bit warmer (March-ish)