If I feel the skin is too light I will give a second coat of green wash to tone it down, I will "blackline" with the black wash where two different textures meet, for example where the arm meets the jacket or when 2 contrasting colors meet such as around the white laces on the back of the leather vest
This model isn't a very good example of "blacklining", I do recall doing some "blacklining" on the dwarf, actuall all of my recent models use this technique to some degree. I won't always use black to "blackline" either, if I'm painting human flesh I'll use a dark brown to "blackline" instead, it looks IMHO, more natural. One note about blacklining, don't blackline everything, if you do it will look too cartoony.
Blacklining is meant to represent a harsh shadow, in real life shadows are rarely pitch black, depending on the color that the shadow is cast upon or the level .... hmmm severity of the shadow, it might be grey or brown, in essence, the shadow will darken the color it's cast upon, not turn it black.
Here's a tip, try mixing the washes, if you want a dark red shadow mix the red wash with either the Delvin mud or Badab Black, you can either wash the entire area and repaint the highlights with you base color or just use your new mixture to paint the recesses
Example: cast a shadow on a white piece of paper, did the paper turn black? Most likely not.
Back to your ending with a black wash, I feel that a black wash dulls the color too much if used at the end, the reason I use a green wash at the end is to basically bring all of the greens together and smooth them out
Sorry for rambling, sometime it takes me a while to get my point across
My Skype is thumper7458 if anyone want to talk painting