Towel girl

The anime render should be the focal point of the sig, at the moment it's a little overshadowed by image on the right imo. If you are wanting that in the sig then I'd reduce the opacity of it down to fade in with the background more.

I'd make the render on the left a little bigger to take up a tad more room (saves you making a background). I'd also think about tweaking the colours are little, at the moment I think the orange is just a little too monotone and not really going with the render used. Maybe think about a touch of pink to match up with the colour of her hair.
So a few colour and render tweaks and you'll be good :)