It is a good beginning but you are right it look too... pedestrian, not clowny enough. It might be in part because all your fabrics are solids and I'm not seeing anything to break up the simpleness of the design. There are no extra pockets or apliques or big bows to pull in the trim and vest colors. Look at the way some of the best clown costumers add that little extra touch.
Pricilla Mooseburger Originals ,
Costumes by Betty ~ Official Costumes by Betty Website and Online Catalog and Costumes by Barbie (can't remember the website right now.)