Funny...I've been only able to get one face right as well. I've been searching online, but no one seems to have mastered it yet.
I also read somewhere...having a large picture of yourself works well. But who has a large picture of themselves laying around. I took some pics directly off my laptop screen, and it wasn't that great. It's all about the lighting. When the weather gets better in my area, I am going to open my blinds and use natural light.