Flesh color contains the three primary colors: red, yellow and blue in different amounts depending on the skin pigment, whether the skin is in light or shadow and whether the skin is over an area with less muscle (where it appears cooler (temples)) or over an area with more capillaries (where it appears warmer (cheeks)). Skin color (like all color) is also painted "in relation to" so it depends on what is adjacent to it.
Practice by mixing your own flesh color that you see in the highlights and shadows your hand. Dab the mixtures directly onto your skin to see how close you are to matching the color.
Practice the effect of light and shadow on the skin by painting a christmas tree ball ornament with a uniform flesh color. Now, light the flesh-colored ball and paint the dimensional change in the lit flesh-colored ball.
Once a basic flesh color is mixed, you must ask:
does this need to be lighter or darker?
warmer or cooler?
more or less saturated?
Here is a variety of limited palettes for making flesh colors:
1. Titanium white, ultramarine blue, burnt sienna, raw sienna, cadmium red light
2. Titanium white, cadmium yellow medium, alizarin crimson, burnt umber
3. Titanium white, cadmium yellow medium, cadmium red medium, cerulean blue, burnt umber
4. Light Flesh tone: Titanium white, cadmium red light, cadmium yellow medium, burnt sienna,
5.Medium Flesh Tone: Cadmium red light, cadmium yellow medium, yellow ochre, burnt umber
6. Cadmium red light, burnt sienna. burnt umber, ultramarine blue
7. Light Skin Tone: Titanium white, cadmium red, cadmium yellow, naples yellow,
8.Darkest Skin Tone: Use #7 and add yellow ochre, burnt umber and ultramarine blue
9. Mid Tone Warmer Skin Tone: Use #8 and add rose madder