I wrote some notes on the paint over. Hopefully this stuff helps you. I felt you used the right colors for the skin and doing the nude upper body was a good choice. Drawing the figure naked before adding clothes will always help you understand the figure better. The concept is cool. I like that your giving her some kind of mystic power. Somethings I forgot to paint in things such as the belly button but thats something you can add if you come back to the piece. Another thing I believe you should look at is the gesture of the pose. Mainly the tail. Look and study snakes and eels and how their bodies move. A quick video search of them will work wonders. When mixing human and animals, use reference even if you you will be stylizing it. I wrote this in but I don't know if you'll be able to read it but when ever you have a question about something, always use reference. That will help you improve the fastest.
If you feel like your lacking proper direction then take one thing at a time. So if you want to learn faces, study from real faces and even your own. If the face as a whole is to hard, then break it down and only do one part like the nose or the mouth. Marc Brunet explains this better in his youtube video. Again I hope this helps and if you have any questions, just write them here and hopefully I or someone else can answer. Keep up the good work.
Lastly Keep up the awesome work. Look forward to more work. 
