Painting skin colors was always one of the most intimidating techniques to master in my artistic career. It was equally one of the most rewarding skills to gain and the best part is that there is a fairly simple artist secret that can help you create a range of skin colors that look more realistic than using a pre-made peach acrylic color. The formula consists of just mixing the primary colors (red, blue and yellow) in a particular order and in different amounts using white to achieve lighter skin tones.
Make a light sketch of the face you are painting to use as guide.
Apply a dab of each color to your palette following the ratio of the following picture where you have twice as much yellow as red and a small bit of blue, depending on how dark you would like to make your skin color.
Mix the red and yellow together, adding red slowly to the yellow until you achieve a light orange-like color. Adding too much red all at once can be fixed by mixing in more yellow. One you have achieved this you can add blue in even smaller amounts and being even more careful to make sure your color does not end up too purple. The key in this step is to experiment and see what tones and colors you get. Add white to tone the colors down to a more skin like appearance. In the following picture you can see my palette and all of the skin tones I made after mixing these colors in varying amounts.