First, a very small rough to find the intention, the posture, the frame.

 

Another quick rough. I start to indicate the eyes, the hairstyle, the hand at the foreground. I also put the letters.

 

I try to to improve the head, the angle of view. The hairstyle is more precise, the tee-shirt appears, as well as the earrings.

 

I am not satisfied with the angle of the head. Also I use a 3D model (thank you Aline) in order to have a right reference. I delete the haistyle to see better.

 

I do another little rough according the 3D scene. All is here. I can do the definitive drawing.

 

Here is the drawing which was scanned. You can note that the ball is not very neat. But I know I can redo it correctly with Illustrator. The "Xbox 360" logo will be got back directly from the Microsoft style guide.

 

I get back my picture with Illustrator, and I start to redraw the lines. I put a few color zones.

 

I hairstyle goes more and more detailed.

 

I am not satisfied with the ball . So I redraw the motif (the curved X) according to the offcial logol. The hair locks are refined.

 

I finalize the look, and try to find harmonious and ligible color bulks.

 

Finaly, I change the grey and the green. I try a few shades under the hand and the bust, but I am not satisfied with it. The result is also visible here at a better resolution.