Well, well, this is the only time I can online for this week. I decide to bring you some tutorials that are useful for you. I once also learned from here and.. many tutorials that I found in deviantart are helpful so I recommend some of them to you. If you like, you can actually search by yourself. There are bunch of tutorials from computer graphic to manual hand drawing.
The tutorials that I list here are for computer graphic.
1. Drawing Anime Face by Crysa
2. Anime Eye Coloring Tutorial by gchanmaiden
3. Tutorial: Coloring Anime Faces by deviantbluebug (specifically a tutorial on lips coloring)
4. Skin Coloring Tutorial by apchi
I hope these would help you improve your skill. Good luck and ENJOY!