I think tall white boots would look good with it. Gumi's original design has white boots with it too. ^_^ Maybe even black flats with little jewels on it? Or a bow? I wouldn't wear plain black flats with the black socks. If you do get black flats, be sure to get some with accessories on it. Maybe even a pretty flower!
If you can't find any with nothing on it , you could probablly buy things to hot glue on it yourself. x3 That's just my opinion. I hope I helped!