So, after some serious tutor work by dwartist (check out his incredible work following this link)
I spent the late afternoon and early evening with two things: trying out a homemade wet palette (something I have read about a 1000 times, but never used myself before) and painting up some proper faces.
The faces were built up slowly from mixing into each other 5 different skin tones by Vallejo and GW. This is also my first time to actually try to paint the eyes properly. The Sergeant's head looks like he got some tremendously huge eyes, but it is the sculpt - I already tried to paint them smaller then they are sculpted. Compared to him, Prodos' Major "Dutch" Schaefer is simply perfectly scaled.
Some of the hints and tips I got from dwartist was trying to add a more natural shade to the skin tones by mixing up glazes from flesh tone, blue and red. The result is a somewhat violet tone that needs to thinned down to almost being transparent. It is not applied like a wash, but instead painted over the areas where your skin would normally have kind of a rosy look to it. I wasn't aware how dark it will become even though the mixture was almost transparent. In the end I think I should have done one step less applying it.
However, this is the work of 3 hours and I never did it that way before, so please have mercy but give me your honest criticism.
Here we go with some pics (kinda hard to focus on such small surfaces with my old digicam)