I really like the faces, sometimes the shading is to hard you should try washes (I really like the GW-Washes).
Washes will make you Paint faster and better.
Another thing i can really recommend is the Sakura Micron Pen for stuff like eyes and text´s.
I don´t really like the OSL at Stalker´s Faces. This Blog really helped me to paint OSL: http://massivevoodoo.blogspot.com/2010/01/tutorial-object-source-lightning.html
I can really recommend that Blog if you want to improve your painting skills.