Love this batwing style top from Ellery. To make your own, grab a black (or any colour really - could look good in white?) long sleeved top with a low back, wack in some small shoulder pads, cut out some matching fabric to look like the rough pattern I have done below and sew it to the top where shown. Make the pieces of fabric you sew onto the top long enough so that when sewn in they hang down past your hands. Throw your black top in some diluted bleach and then shred the edges of the wings if you want yours to match the Ellery one.
Image: Ellery via Peny Lane