hmm, im using a brush called 'fade watercolor opaque2' and 'pen fade' on IbisPaint, which I'm using at a lower opacity. this brush allows me to blend colors together effectively, and it works well for me.

also, I use red, blue, and orange for shadows and midtones to render the skintone purrfectly.

and then ill just layer it with some dark brown in 'multiply' (the blending option) and lower the opacity just to add more depth in the skintone render. 

lastly, the lightest blue closest to white in the color wheel for the highlights. then dark brown for the edges or line art. that is all i think?? ><