This image is from a photographer called Chaf on Model Mayhem (#1895650). Along with a lot of skin retouching and blemish removal, this image I felt could be enhanced by some digital make-up. In this instance I created an empty layer above the background and sampled a colour from the lips (I had adjusted the hue of the lips earlier) and painted on the layer with a pressure sensitive wacom tablet, I then changed the blending mode to colour and reduced the opacity of the layer to taste. By first painting on a normal layer gives you a better idea where exactly to add in the eye liner and blusher before changing the blending mode to colour. By sampling the colour from the lips you help balance the colour palette of the face, if you wanted to change the colour of the added make-up you could just add a clipped Hue/Saturation adjustment layer to your layer stack – this way you would be just affecting the colour of the layer immediately below it, not the entire face.