The eyes are a good place to start. They are not pokemon VS sprite style, for starters. Barring some of the new Gen V ones the eyes come in three broad categories and have a different "feel" to them.
The big anime-style eyes:
The smaller anime-style eyes:
And the tiny-dot-in-a-big-white-eye style:
Except for the last category none of them have any white showing at the bottom of the eye. Generally it's a colored iris, usually dark, with a light grey to one or both sides. The faces are around half light and half dark with more light on the big eyed sprites for that extra bright quality. Too much shadow makes them look sinister, but even those need some light on them and I don't think your first sprite has enough of that. Too much shadow and the whole sprite overall looks too dark. The official sprites have varying light and dark areas and I think it makes them look better. They're more dynamic, I guess you could say.
I also think the first sprite's eyes are too large. If you want something more 'cool' or a more mature feeling you need smaller eyes to reflect that. Also look at the shapes of the mouths. They are longer on the faces that are smiling or grinning, generally. (These aren't the best examples, but you can look at others). I'd suggest shortening the mouth or opening it a little and adding some of that white that gets used there.
You have some complicated hair to work with. Generally you'd want just two shades for the main part of the hair (light and dark) and maybe a third darker shade for line work. Hair highlights as you've made them aren't used much and when they are they're not as large. Having multicolored hair is another challenge. I can suggest removing the outlines between the two colors. I think it would be okay to have the black and red touching and it would mean you don't loose space for outlines.
On the other sprite you don't need to have as much detail in the hair. You should also alter the way the head is shaded since the light on the body is more from the top and the head has some sideways lighting going on. Tone down the colors, too. The green especially is too neon. The eyes should not be exactly the same shape, and I don't know why you have no dark pupils in them, but it's of course not pokemon-style to have them that way. Also, it would be okay if the mustache extended past the outline of the head, but you seemed to shorten it a little on left side.
Yeah, I think that's enough for now. @_@