If she's a spirit, why don't you make her atherial looking by giving her a transparency and glow? If you double her colours, and put a gaussion blur on the higher of the two levels, it'll give a glow that's very soft. If you then put some green underneath the glow (without loosing the details) then you can make her look slightly transparent and still bright. IT's a thought.
Well, there's a few reasons why I don't do that. One - she's not separate from the background.
Two - she already has the Gaussian-Blur glow. It shows up pretty clear on my own monitor, but I think some monitors don't pick it up too easily so it gets lost.
and Three - I'd have to check, but I think I've already flattened the whole image (or almost the whole image) since when I was making it it just kept getting too big for my computer to handle without jerky movements.
I think I actually like the texture idea best, though. It will be really cool if I can get her skin to have the texture of bark without changing the colours too much.
A texture is better then I just thing she needs to reflect some of the earthy tones of the picture. Make her look less human and more naturalistic. The colour theme is beautiful as it is though, so don't migrate too much from it ^^