The Lines;
#1. Put the layer on screen, change opacity to 50 - 60 %. For all the lines around the face, get a colour like dark brown, and colour all over the facial lines.
#2. Do the exact same for the next step. Put layer on screen, and choose your hair colour. Do the same, use a 70 - 80% opacity.
#3. Screen the rest of the clothes with various colours, for various parts.
The Actual Colouring;
#4. Pick a skin colour, and put it on multiply. A nice skin colour. Being honest, BlackWolf, I'm not too fond of your salmon pinks. =( Opacity, maybe 90% depending.
#5. For shadows, use the exact same colour, but go to that spectrum color thing, and pick a colour near the exact same, but perhaps a shade or two darker. The shade can't be too obvious, though! Put it around the obvious places where you'd think the shadows would fall. Opacity is 40%.
#6. For darker shadows around the direct sides, use the same colour, but multiply it. Opacity is 60%.
#7. Do the same thing for the rest of the clothes, and whatnot.
Hair Colouring;
#8. Now, pick a color you like and start coloring (multiply layer as before). This will be the base color since we'll be doing many layers for hair. Opacity around 80%, depending.
#9. Now, shadows. Pretty similar how we did the skin shadows. This time use many different colors and layers and opacities and see what happens. I usually leave all of the layers on multiply. Soft Light & Linear Burn can look good as well.
#10. Create three (multiply) layers, and use different shades of the hair colour you chose. Of course, they all must be somewhat similar.
#11. That should be enough of shadows. Now some light! Pick a light brown (or yellow etc), new layer and set it on soft light. Color some parts where do you think it looks good and then set the opacity around 40%.
#12. In case it doesn't show anywhere, do this too; New soft light layer, pick brighter color. About the same opacity. But this time add the color on the parts that you already soft lighted, not everywhere, just to the places you want to be the lightest parts.