Honestly, I wouldn't "add" anything to it that's not there. That design is interesting enough as it is. I think if you do really well getting EVERYTHING you see in the images there, you'll look awesome and people will love it for what it is.
At most, I'd be sure to get the "deku-ish" texture across on her head. Don't make it too smooth-looking. This costume just needs simple clean construction and a great paint-job, not the presumption that adding details makes things better. That's the Achilles' heal of simple costumes, getting everything that IS there as accurate as possible. Proportion is the main thing with this one. Sometimes the simple characters are more awesome than the ones laden down with unneeded gingerbread.