The Shepard Paine technique, which worked for me for many years, is to paint a blue or brown stripe starting at the eye brow and going down over the eye area, and then ending at the top of the check. Then paint a black, thin stripe down the middle of the first one in the same manner. When that's dry, just paint the base flesh tone around the eye leaving only the eye area visible, and bingo, an eye.
These days, I just dab a dot of color and then a smaller dab of black after the color is dry. I do the white dot mentioned above as well. An artist friend told me once that the way to get the eyes of a painting to follow you around the room is to put the white dot in both the 8 and 4 o'clock position (or wherever, as long as you have a two dots opposite each other). I've tried this on a figure a few times, but with limited results.