Stop using lineart so much. I can tell your process is 'draw lines, then fill in textures as an afterthought'. Your work looks really flat because of that.
Think in terms of volumes foremost and outlines secondary. To render a volume, you have to use value- that is, you have to draw any given object with shades that change more dramatically than what you've got going on here. Your arms and lower body look bad because you're not thinking volumetrically; the horizontal gradient stripes are literally a texture-fill that doesn't take into any account the context into which it was placed. Similarly, your arms are just long stripes, that don't show any anatomy or muscular information. (Bandits are big and muscular, right?)
Also, have you considered the perspective here? What exactly is the camera angle doing? I can't tell if the silhouettes behind our infamous bandit are people wading in a lake or ghosts floating in the air, because you drew the background as if we're looking at it from above, but you've drawn the character as if we're looking at him from below. It's really weird, and it confuses the viewer.