Models, as detailed as some might be, still aren't able to show off each and every strand of hair, so sometimes you might end up with a clump of black, green or whatever color the hair is. Though you might be content with a single color tressed figure, real hair has highlights and sun streaks. To get this effect, some people use up to five different color layers, one as a base, one as streaks, one as highlights, so on so forth. Another way to approach this is to layer the hair like you might paint a decoy feather
Do your model's faces look too drab? Are they just solid blocks of color? In that case, here are a few tips: 1) Around the eyes or under the chin, you might want to shade a bit with a thinned, faint orange tone 2) On the cheeks or the tip of the nose and chin, you might want to use a hint of thinned white to make the areas lighter 3) You also do not want to make the whites of the eyes too bright, but dull it down a bit 4) And finally, "blend" the retouched areas with a little thinner
To finish off the model, you need to put in the eyes. First, figure out where the figure is looking towards, and know that pupils are usually not directly centered in the eye, but rest a touch higher than that. Eyes can make or break a model, so get those delicate brushes out, and good luck!
In case you are wondering, this is what the finished product should look like:
