Next step is hair. New Adjustment layer, etc. It looked like brown hair would work the best based on the original, so I went with that. Raised magenta and yellow up, some small tweaks to cyan and CMYK, raised the black a little. I have no formula for colors, just keep messing around until it looks good. And remember you can always go back and edit it later.A key point with hair: When you have whispy hair that partially covers skin or background or whatever, you will want to go to your mask layers and use a the brush tool to work with the layers until you have no overlap. You can also selectively blur, smudge, and use greytones in the mask. You want to avoid color overlap, because it creates an obvious line of color across a section of your image and makes it look bad.A note about eyebrows: If they have black eyebrows, you can just color skin tone right over it, otherwise, color it the same as the hair and make sure you have no skin tone/hair color overlap.Getting close: