thumbnail looked like Keanu Reeves meets Butthead, got me interested :)

I like it, colours are nice, looks like you use the same brush what program do you use?

Have you considered exploring different brush types/textured brushes at all.

One think I found that helped me capture likeness in a face was to use a crappy bulky textured brush, and work on a really rought sketch firstly, But if you have a reference photo printed out, or on your computer try focus on one feature at a time, Id draw faces from a magazine, making a circle with my hands and place it around the feature i want to focus on, or use a toilet roll, so you ignore the rest of the face and just work in the shape of that one feature, being either eye/nose cheekbone ect.

But working in the basic shapes for the key features before getting into the detail helps alot also.

Apart from that good piece <3