Fooling early season birds can be done even with a few mistakes but late season birds take a little more effort to decoy in.
When the temperatures drop and your decoys become frosted, it is best to get the frost off before you start hunting. All it takes is a few passes with a small handheld propane torch and you're good to go.
Leaving the frost on the decoys is enough to flare a flock of birds. The little extra time it takes to defrost your decoys will be worth the effort.