I know you're looking for digital help mainly, and for that I'll give you one solid piece of advice: Watch your textures. In some spots it almost looks like you used some filters, which cheapens a piece (I don't mean you DID use filters, but you definitely were using texture to make up for errors in painting technique and anatomy and that can have the same overkill effect).
My real advice though is the advice I already know you don't want: Work on your anatomy. I can tell you have a great imagination, and I love where this is going, but anatomy is waaaay more important. No amount of photoshop magic is going to make these pro quality right now. If you really want to practice digitally (and I don't blame you, I love PS), then I suggest using a hard round brush ONLY (with opacity set to pressure), and work in black and white for a while until your values are more consistent. And use reference. Lots of it.
You'll be great in no time flat.
'Cuz life is full of your regrets, and I should be one...