tough to explain with just text, but to make a long story short: take a picture of a leopard en cut and paste different pieces over the face of youre subject, use warp tools and stuff to "fold it" over the face and then start with layer masks to fade out the acces bits and pieces to meld the pieces together. After that use a blending mode like overlay to... wel uh blend the pictures. Play around with the colours and lightning, shades, hue saturation until it looks natural. Thats kinda what I did in a nutshell might be easier; faster; and even better ways to do it, you might think of one of youre own, photoshop is just like a swedish pocketknife loads of functions and the user determines how he uses it. Best way is just to fiddle with al the different functions and follow some tutorials just to figure out what other people do with them. And you'll create a style and technique of youre own
Haha okaay, i've seen something sort of like this, but not like this (if that makes sense) which i want to learn to do, the woman/girl who did it is a local photographer but never shares how she does stuff