There are a few still online at http://skindom.planetquake.gamespy.com/tutorials/ The main thing you need to learn to be able to paint textures without any help from photos is to learn to paint, though. Colour theory (although that really just amounts to getting a feeling for colour, rather than really using the theory…
I just finished my first low poly character but I've never even touched photoshop other then to do basic manipulation. Are there any great tutorials or forums to get you started in the right direction when it comes to making realistic facial textures that DOESNT include doing textures from real images.....I want to do it…
The best advice I could give you is to show what you've done, and have us give you advice on what to do to improve it. I understand you're finished with your last one, and you might not be 100% happy with how that turned out, but could you show us that one to begin with? If not, just start a new one and let us take a look…