Lol, floating head.
I would have made the render a little smaller so that a little bit of the body ( and I'm guessing her arm over her head) were shown. I like the colours and lighting thought very good job on that. Text is good too, personally would have put it a little closer to her but it's fine where it is now as well.
Yeah, just a few details to fix here and there and try playing with the dodge and burn tool to add a bit of depth as well.
All in all pretty kicken sig, nice job.