Well the only thing i can say about fixing the drawing is that the head seems a bit odd... the jawline seems a bit uneven and the hair starts too high, eyes are the centre point of the head so remember that if fixing it,however hair tends to stick up a bit so the eyes don't have to be completely centre. If your colouring the eyes red then remember that eyes have a:
pupil: the black part in the middle
iris: the coloured part, in your case red
sclera: the white part.
I tend not to draw humans with red eyes but if you are going for a realism just remember that red eyes only naturally occur in albinos due to lack of pigmentation.
Seeing as your colouring in paint I would highly recommend a cell shaded approach. i tend to cell shade. cell shading means not blending colours and thus,using a limited colour pallet in whatever your shading. but that doesn't mean you should just stick to only two colours.
I just remembered a quick sketch i did i think a month ago
http://aeonzen141.deviantart.com/gallery/?catpath=scraps#/d4u6sz9 if you look at the skin you can see as the tones got darker i went from a very light orange to a grayish purple colour. I recommend you look at the colour wheel to understand why i did that. Remember this is only a quick sketch so i didn't put much effort or time into it (i think i spent around 13mins) so it's messy.
If you need help on anatomy or colours, look at tutorials.