I would still keep it simple - A different coloured jacket/cardigan/top maybe a belt possibly coloured shoes might give outfit something extra without taking away from the nice style of the dress. aelida.com/.../blazer-with-black-dress.jpg
depends what look your going for dressed up or casual. for casual I'm a sneaker head so i would wear the dress with a long khaki bomber jacket with adidas superstars originals and an adidas baseball cap. For a dressed up look probably a waterfall in a camel colour with either a stiletto or ankle boot if you want a more feminine touch a fur gillet layered over the waterfall coat. my personal style.
definitely wear your hair down, maybe curl it a little so it's wavy. Some big dangly earrings and a belt would go great, you can even try rolling up the sleeves and wearing some bangle bracelets. You could try necklace layering as well. Also a fun pair of boots would brighten it up! Hope this helped, I am no fashion expert lol! try looking some ideas up on pinterest!