Goin on what Emtch said yeh I agree it needs more contrast and a bit more saturation, im not totally aware of who this character is but this is what I'd do from here.

<< Edit with green in skin << Edit with red in skin

Some more colour in the skin imo more than anything and instead of greys to AA to black from white and on the skin why not use something more colourful for variation. This would work with a red or green.
Also be a bit more daring in sharing palette colours, hue shifts and all that malarkey. I've tried to improve the AAing too, parts look a bit blured while other parts could do with more AA. The dark red of the tongue can be transfered to AAing the hair, as will a shade on the teeth if altered slightly. May not be your thing but colour sharing can sometimes improve a piece and keep the colour count down.

Do you not think it's a bit too big? 

'Pixel art' would be lost on a piece this size imo.

Eh?

Hes trying to translate an album cover into pixels.

Whats wrong with that? That takes skill and you improve, as long as you don't trace.

Yeah of course there's nothing wrong with it, Just if he's going to re-create it, whatever medium he uses it will only ever be as good or worse than the original reference. It's setting your bar low for kicks and giggles, sure you if you can recreate someone else's work to perfection you may be quite pleased with yourself and I know it's not exactly easy, you could do it masterfully. But in terms of creativity you're not going to advance atall unless you take it in another direction.

It's just a personal preference from seeing people I've known from back in highschool where one kid would paint famous pieces of art like the mona lisa; everyone would gather around like 'woah' thats amazing, but in comparisant he hadn't picked up shape and form ultimately just copying what he saw and not taking any understanding. What would he have learnt from this? Tell him to paint a real life woman in the same way, I doubt the end result would be as close. Also right now in university someone I know has been drawing Anime since he was 12 with hundreds of full sketch books, he's a pro and would definately know how to draw it better than anyone else I know, honestly really professional. But our last project we were told to start drawing from observation, it was so funny. You could see the fustration in his face, it was like watching a toddle draw for the first time, I just believe there's only so much you can learn from just someone else's work. Sure there's nothing wrong with direct copying if its all legit, I personally don't think it achieves anything.

I'll give a bit of help.

First off you need a solid set of colours for your skin, more than anything you should be worrying about applying depth correctly, this will ultimately shape and define the character. I'd first start off by plotting out where everything is roughly and slowly start refining it to force the details you want to show. I think of it as bringing something blurry into focus. I don't know how clued up you are with AAing but something of this size can really do with smart use of this to trick the eye to show the details you want.


(im struggling to get a decent copy of Photoshop atm so I just nicked these colours from Shrike. Did this on paint  )

You're pallete can be really useful for adding those details like a slight red tint which would be used for lips and add some needed colour variation to the skin.

What are you hoping to learn from this? If you get this bang on you're still not really achieving much. Why not take it in another direction? Be creative.