Hey there! A study, we love to see it! I tried to adress the areas you've pointed out, so let's take a look a them. The Eyebrow area: I think the main struggle you've had here is the hard edge between the two values. This makes it stand out quite too much, because the value difference is huge towards the forehead. As a result, I tried softening the transition between them and therefore introduced some brighter values. The Neck and the upper lip: I think these were what looked most unnatural to me in this study. I get, that you approached this to be stylized but to my extent, these were pushed a tiny bit too far in order to still work alongside the other parts of the head. I generally moved the whole mouth upwards a bit. For the rest, as you can see, I pushed around and softened a lot of stuff. This is just done intuitively by observing the reference image. You'll improve that skill rapidly, if you keep on doing studies like this! I hope this helps and keep em coming of course!
