Not bad. I might be a little picky with this but..
you should've tried to get rid of the blue on her hand, it's pretty distracting. The render should be a bit closer to the center imo, although that's a bit up for debate. There should be more foreground effects (especially on the right side).
Can somebody give me a magnifying glass please? XD
Nevertheless it looks good, though there are some small things which I had like to mention:
The lightsource has been placed on the wrong side, the shadowing is on the left part of the render and the lightsource is also coming from the left side.
Perhaps a little bit blending with the soft eraser tool
It is Sivir's winterskin, so perhaps you could have made it a winter themed signature