Now that is a Hottie!

I love the colours, C4D effects and how it has a very simplistic feel to it. The signature is not overcrowded with details and you can easily make out the girl.
I do think that the shadows are all wrong. Have a look at her hair and left arm. The black suddenly ends, but the background is one solid consistency. If you add a Black and White gradient over the top, you may be able to adjust these lighting effects so that they look more realistic. Use settings like Soft Light and Overlay to help you along, and don't forget the Opacity settings.

Her right hand also looks like it should be on the border, not a few pixels away from it. A similar thing could be said about the left where I think she should hold the border. If her thumbs extend past the sig, then so be it... Let her look like she is leaning out of a window of some kind.

I wish when my neighbour leant out her window that she was this hot.