I have had some success with creating a black mixture that includes nearly any black (Mars, Ivory, Lamp they all have a different look) and jaune brilliant, or flesh tint. This makes a warm dark gray, this can then be shaded with whichever black you used in the base. Highlights are made by adding more of the highlight component you chose to the base. Wet on wet you can usually get away with adding the highlight component directly and blending.
Mars Black-very pure black
Ivory Black-tends toward brown
Lamp Black-tends toward blue