Process

In case anyone is curious here are some examples of my process.  It's fairly straight forward using a traditional approach of lines to value to color. 

My concept process:

Some helmets I made for a friend of mine to model.

First I just made a sheet of anything that came to mind.  The idea was to use large blocky shapes with harsh angles.  He ended up liking number 10 a lot and elements of number 3, 6, and 12.

So this was me taking elements of 3, 6, and 12 and running with them.  The idea was to be a bit tighter to get an idea of what the final helmets might look like without wasting time on trying to make it look too pretty.  Number 4 was the winner out of this batch, the cross shape gave him a nice menacing look and was also reminiscent of Bobba Fett, we thought.

These were the final orthographic views of the helmets ready to model.  The polished versions of the original numbers 6 and 10.  The middle helmet was from a different sheet of rough ideas but used the same process to make.