My latest skin technique is a layering one. I go from Dark Flesh to Tanned Flash (Vallejo tan) to Dwarf Flesh, leaving a bit of each color in the recesses:
An older, simpler technique I did was Tallarn Flesh with Devlan Mud, then Tallarn Flesh again on the raised areas:
And another one I've used is just Dwarf Flesh with Ogryn Flesh wash and a Dwarf Flesh highlight:
Of course you can layer this by then doing another layer of Dwarf Flesh and Ogryn Flesh wash over and over again: