I think I'll just go from point to point on this one.
Her tattoos are very lovely and fit the characters image and role as a forest guardian. The greeness in them also adds the feeling of nature. Still, the shape also remind you of wind or waves with their roundness, therefore doesn't match the forest theme.
Some colours are sharper and the drawing is more detailed towards the hair, her arm and face. It looks good but makes you look almost only at the center of the picture and leaves the rest rather unfinished. If you've made such a pretty picture, make the whole picture so.
This piece is a definite story-teller, and I absolutely love that. The environment, the character's posture and expression, and little details like the twig in her mouth all come together to sell this as a moment in this girl's life. She feels alien enough to be a fantasy creature but real enough to be believable. Well done!
I think the composition is excellent. The eye is encouraged to wander around the whole painting but always comes back the focal point around her head and shoulders. There's plenty of rich detail to take in even in the more loosely-defined parts.
Speaking of which, I love the atmospheric perspective on her arm and leg. Makes it feel like she's sitting just inside a ray of light that's peeking through the canopy.
My favorite thing about this piece is the texture pattern on her skin. It makes her seem like a carving that's come to life, and that's just rad.