You surely put some work into it. You could try some noise/ graininess for the dust, to add more substance to it [look at Gaara [Naruto] wallpapers for some examples]. Very nice touch with the rays of light in the background that follow the same diagonal movement as the character's arm. The sky could also be saturated a little and given more volume. A nice trick would be to curve the line of the sky [the clouds], because this would give the image a more dynamic look. Right now the clouds are just plain horizontal. Also, giving the clouds 'closer' to the character more contrast, a bit of texture and making them a bit bigger and more saturated would improve the overall aspect.

Something to consider about Ichigo's skin is that when the light color of the skin meets the shadowed one, that particular area is more saturated in color. This will give the skin a more natural look. Also, the light part of the skin is of a warmer tone [red-orange-yellow], while the shadowed skin is of a colder tone [slightly more purplish/bluish].

Anyway, it's a very nice piece of work, so keep them coming!