1st, select some mallard flank feathers, these are usually mottled and closely resemble the natural wings
2nd, select just the tip of the feather, and treat it with your favorite flexible cement. Use your fingers and work it in good, making sure to keep a nice flat, rubber-like feather.
3rd, after your feather has dried, lay it on some clear wing material that has also been treated with cement.
once this dries, cut to shape, or use a wing cutter. it now has a clear, shiny outside, and mottled (natural ) look.