It's coming along really nice!
The environment has a nice feeling altogether. Making her stand out too!
I did a little experiment. Played around with the saturation. Felt colors needed to have that vibrant punch. Try and avoid near black tones. Instead use a slightly darker tint of a desired color. e.g. pink > dark pink or deep purple but not something toward black. Situations do differ however.. in this case it's the outdoors, clear sky n all.. if it was an indoor shoot with studio lights, colors will look way different. There, black can work in some way. Depending on the lighting rig.
Somehow the .zip file is not displaying. Here's a download link containing the .psd file for you to check out.
Meanwhile .. notice i duplicated your whole image and set the blend mode to "screen" ; you can do this after you've completed the painting. Then place all the adjustment layers over that image and finalize the overall color treatment.
Indoor dark - (notice her skin)
Best examples :
Indoor light -