How complicated are you looking to go?
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:
Alternately, Dwarf Flesh with Ogryn Flesh wash works well enough. Camo on the top Catachans is Catachan Green with stripes of Chaos Black, Calthan Brown, and Camo Green, all highlighted, and followed by Devlan Mud.