Since everyone already has suggested the outfit, then I suggest you look for tutorials on how to do his facial hair/boyish appearance. So you'd need to look for "Female-to-Male Tutorials" and experiment with make up...As well as "flatten" your chest if you want to be exactly like him. So I suggest buying a binder.
Tutorials for Make-up: http://cosplaytutorial.deviantart.com/gallery/?25172877
Hope this helps! ^.^