Wow! You did a great job improving!
A couple things that stand out to me are the cast shadow and her horns. The horns look like they don't connect properly right now. It's an easy fix just paint hair over them at the base will do it.
For the cast shadow remember that all shadows (at least in lighting setups with one light source) are going to be the same value range. So a cast shadow from an object on to a form will blend into the form shadows as if it's all one shadow. I hope that makes sense, took to paint over for example.
Your darks could use a little more detail in them and could stand to be a little lighter. A good rule of thumb is to not go under 10% on the brightness slider. I know you said you still have yet to render that area yet but I figure I'd point it out all the same.
The anatomy looks fine for the most part. The arm and the abdomen are the ares that could use some work. Take a selfie while doing that pose, that should help with the arm. Find some ref for the abdomen too.
For the background the gradient of the trees is looking a bit flat and stale. Adding some texture and variance to it will make it look more organic.
I think the sky could be vignetted some more. In other words make the top darker.
The composition isn't bad, it's squarely solid, literally. You could play around with it, making it more vertical. Maybe having the top fade off into space and stars, that could look cool. It might be a bit to broad right now. I feel like there may be a bit to much empty space on all edges so maybe zooming the piece in a tad would help.
I think some leaves and dust blowing in the wind along with her hair would add a lot.
Here is a quick paint over, I hope it helps give you some ideas and that this was helpful and thought provoking.
