Doodles and Finished Pieces

[Star]

I think some contrast will really help out. Also, maybe use more vibrant colors for the shades will really make it pop out? What will also help is using the shade to "shape out" the character. Like I see around the arms where..it kinda seems like "banding". Take advantage of the shading.

Also, maybe add some kind of shade effect in the eye? So it kinda pops out more. Like Zac stated, try to sway away from the airbrush look; especially for illustrative pieces like you're doing.
Overall, I really like the character design. It reminds me of a Kirby enemy.