One way, if your using photoshop you can add texturing, not patterns, but texturing, like I believe its fibers (I have not done metal texture for a while and not looking in photoshop for it) but you can make the fibers small and look like lines. then you can add a radial gradient so that it is more shiny in the front of the head and darker around the edges. Or whatever, but make the colors gray and black of course then it should look like metal.

This would work really well with this type of head, and not to bad man.
7/10