alright, i must say. i'm terrible at critique. although i will try my best!
i have given you full stars for everything, because i believe this is a very beautiful piece of work. i adore the colours, and the shading technique you have used. the line art is also very pretty! i haven't seen anything else like this, so it is very original in my opinion. the anatomy is absolutely amazing, i also love that beautiful floating pose. it looks very calm and relaxed. the rainbow sky is just amazing, i don't think many can pull off such bright colours, and so many of them like in this piece.
hmm.. i'd say the line art on the face and wings is a lot cleaner than on the lower body, so the only thing i'd say, is make the line art clean in every part of the drawing. but i really love how you used a thinner outline for the face and wings, which are further away, and a thicker one for areas that are closer.
i really hope this helps ^^