When mixing skin tones, you don’t have to make it complicated. There are various formulas available, even whole books dedicated to mixing various skin colors, but you can get a nice range with just Yellow Ochre, Raw Umber and Burnt Sienna plus white and black. You probably already have these hues (colors) in your stash or something close to them.
These color slides show each hue washed out with water to illustrate the range from opaque to sheer. To create your own slides, simply dip a no. 8 round brush in the full-strength paint and put a bit on the paper, then rinse your brush with water and use the wet brush to slide the paint from full strength to washed out.
These slides show mixes of two colors with varying mix ratios in the middle. This is a great way to see the varying colors each combination can make. I’ve used only Yellow Ochre, Raw Umber and Burnt Sienna to show the wide range of skin colors you can achieve with this limited palette.
If you want to match a color from a different brand of paint than what you have, find the pigment name and number, which is usually located near the paint name. The pigment name will be abbreviated (e.g., Primary Red = PR). If it includes more than one pigment, multiple pigment abbreviations will be listed. By matching the pigment name and number rather than the name of the paint, you can work across brands and find the correct color.