As I came from a "massed fantasy armies" background, I get used to just shadow the eyesockets.
For most of my minis, a dark shade of the skin color works perfectly, as the eyes are not seen once the mini is on the tabletop anyway.
But for some character figures, if I "feel the mood" I'll panit the eyes, no matter how long it takes.
Anyhow, I use the simple method of painting all the socket a darker than skin color (for humans dark brown or black), then a thiny white or ivory strip a little larger than needed, and a black dot in the appropriate position (usually the center of the eye, but sometimes you want your figure to look sideways). After that, I "trim" the upper part of the eye with the same dark color, to simulate the upper eyelid, thus minimizing the "bug eye" syndrome.
Hope that helps.