First off, imagine that you are designing the lighting for a big Hollywood film. Ok, now how do you light the rugged hero? He’s beat up, but he’s tough enough to get through it all. You go ahead and light him with some somewhat harsh lights that accentuate all of the lines on his face. He looks tough this way, with a clear defined chin and cheekbones.
Now go to the woman playing opposite him. This time you want her to look attractive, so you use very soft lights. The lower contrast of these lights gives her a very different look. Some of the wrinkles and imperfections on her face get lost in the low contrast lighting.
That is the fundamental difference between painting male and female faces. Usually, you want to paint male faces with quite a bit more contrast than female faces. I’ve heard of a lot of different methods and tutorials about how to accomplish this – you can thin down your highlight layers with matt medium or water to make them translucent, or you can use a lighter shadow color than with male faces. Anyway, I’ll just point you to a few tutorials on the specifics.
Beyond that, there are some needed details you can paint in a number of different ways. Makeup, for example, is a great detail to pick out. For lipstick, just mix a little red into your flesh tone and paint the lower lip only (paintint the upper lip makes her look like she’s got too much makeup on, or like she has huge lips). Eyeshadow and blush are added in essentially the same way- you mix a little bit of your color with a lot of flesh tone and apply it lightly.
In the end, painting female faces can be extremely rewarding.