The first thing that jumps out to me is the proportion of your image. It's too disproportional, the legs are too long, the arms are too short, and the mid-section is fat too small. I would try to fix those to build upon your image.
The colors are nice, i think the contrast of the clothing to the skin color works well, and i think the pose is good.
I understand you said your technique was 2D, though i would say some basic shading would really help bring this image out a bit more in terms of impact.
Overall, your piece is pretty good, i could see thing being a game sprite or being part of an animation, the simplicity of the piece helps make it usable in those aspects, so generally your piece is well done.