I've never been one for white eyeshadow unless it is put on by a professional or used solely as a highlight shade.
You should either off set the dress with a dark color, or if your eyes are a dark blue/brown or something like that, by a silver eyeshadow pencil or roller and use that. other wise black or gray. Apply all shades only to the crease with a sponge tip applicator and then into the crease with a fine haired eyeshadow brush. Use massacre AND eyeliner or it will look weird.
hope this helps you.
-Alice.