Simple buy cute you can use another color more visible for the shapes on the background

She is always pure and pretty. Her unstable funny character make me laugh. Soft colors in the wallpaper make her be more attractive and charming.

I see the shapes as well. There's something more that needs to be done with Mikuru herself. The outlines the takes shape of her Left Arm and from the hair is rather not-so-smooth unlike the other lines which is somehow nicely done. Perhaps its because when you resized it then it happened? If it does then make the lines a bit thicker than the original scan you vectored it with. And lighten up the colors a bit so the shadow and shades won't fight with the major colors. It does hurts the eye after all.

And somehow the shadows of her body seems to be a little of. But if it is rather an abstract work, then I guess it would be okay but I guess it isn't since you didn't mentioned it.

It is a great concept you're starting to do right now and you can improve it more if you have time to do so. You can transform it into a better wallpaper if you pay attention to the suggestions of this great wallpaper makers like Red-Eclipse mentioned earlier ^^

I'll keep an eye on this work to see if it will develop sooner or later. Cheers!

The scan is so cute and you made it more soft, nice!

But I think the texts should be more clear.

Anyway, good job! :)

Clean and nice job..
the background color should make it ore colorful..

Mikuru's so cute