Hey not bad. I think you're well on your way to thinking in 3D
Main problem I see now, which kind of makes the others hard to see, is the construction of the face. Keep working on learning the shape of the face. I think if you learn that in detail, you have enough rendering skill to make it look good. Right now it looks like you're flying blind. I like the color choice, too. One more thing, make your canvas as big as it needs to be. Right now you're squishing things to fit the frame. No bueno.
Here's an edit I put together. I'm still pretty novice when it comes to this, it's really hard. But despite the obvious flaws, I hope you can take a few things from it.
