I saw this thread and started fangirling BECAUSE THIS SHOW IS AMAZING
It seems she just has an apron over a dress... though I've only seen old apron patterns that my Grandma used to use so u___u I'm sure you'll find one in a costume book, there have to be some.
(now I wanna cosplay a fairy XD)
Next Con: Katsucon 2014
~Ruby Rose - RWBY