I say that's pretty nice. But just as Peter said, you could try and learn to enhance the work. Some areas of improvement:
- You could try and add a tribal design on the back with offset, though no need to be too complicated.
- Maybe add some sort of facial feature, eyes preferably, and make them some how stand out, yet if it is glow, or just a very eye catching color.
- Add color, but this really just optional, just that black and white looks too plain, also maybe use shades of grey besides fully black and white.
Keep trying, each time you will improve as you'll see some areas which could be created better. I hope I helped. =p Remember to practice, practice, practice!