coat the thing in some type of very flat clear coat. make sure there is no chance for the sun to glint off it. rain and sunbursts are a bitch coz the rain (waves do the same thing) will shine it up and then the sun comes out and makes it look like a disco ball.
Are you coating the wings or the body or both?
I coated the wings after sanding them with light sandpaper because they were waaaayyy too shiny for me. and I coated the body just for the heck of it since I have noticed water will run off decoys with a flat/heavy clear coat faster than just the factory flat paint.
:dunno:wether that was the key to success or not I don't know. but before I painted the wings and clear coated the miserable thing, birds wouldn't come near my spread unless it was super nasty weather. after I painted it up I was having birds land feet away from the wind duck on bluebird days with just enough wind to keep the wings turning.... and thats good enough for me!