I'm not great ot people, but to blend the tones..set the brush on the airbrush about 2x2 or 3x3 set the blend button on...set opacity and flow sliders to just a bit over half set the color to the lighter tone of the ones you are blending and go to it.. you can also use additional layers to blend over areas... talk to some of the good people drawers for more.
drawn in 10 min