Martin, first clean your figures with a good anti-greaser then them with a primer such as white acrylic, then paint them as you would dress a person from the skin out.
with the eyes add a tiny drop of light blue to the whites so that you cover the complete eye socket then paint the eye as a round ball with a flat top and bottom, miix a little darker blue with the white and draw a line across the top and bottom of the socket. When doing the skin always mix your own colour, yellow, white, red, you can choose the shade you require this way, you can use a darker shade by adding red or lighter shade by adding yellow, put a drker shade around the hairline, under the eybrows on the sides of the nostrils and the lips. You can get a better idea of this by placing a torch or small lamp to shine on your model from the angle you want the light to be and check the shadows. Hope this is of some help bigH