duplicated mountain layer, added light filter on color dodge, layered on lowered opacity and darkened selected areas with a mask (brushing out the brighter areas on a low opacity brush...)
step 8 of 16
maske dout skull from "Deer Skull 1" by ~markopolio-stock at deviantart.com....
increased red value, added inner shadow...
duplicated mountain layer and masked to fit skull....layered over skull for rockier texture....
step 11 of 16
duplicated skull layer again, added light filter, lowered opacity and again darkened bright areas with mask
step 12 of 16
used "RockJagged0016 (Texture: #25545)" from cgtextures.com to add rocky background.... placed the image, duplicated and placed on the other side, merged, darkened levels, adjusted hue. and layered over black background on lowered opacity