A friend asked me to do him a favor. He wanted me to turn his original picture into some star-trek figure... As I start trying doing i realized that it was to hard to do that head-structure onto his pic. So i started to work myself into verctorizing today and tried to change his picture into vector and now i try to put the typical parts of that star-trek guy into the vector-pic

This is how it should look like:



This is his original pic:



This is what i achieved so far:



Have you got any solutions for the head-stuff or any advises or comments on my vector-art?