this is a rather simple way of paint ork skin.

you will need: large brush, wash brush, black primer, ork hide shade, snot green, thrakka green (wash),

paint your model black (duh). Sorry about the camera quality. I don't have great light.

apply ork hide shade with the large brush to all areas of visible skin. sorry i am using old citadel paint but for those who have no idea what i am talking there is such a thing called the paint conversion chart.

once ork hide shade has dried (you can use a hair drier to speed this up), highlight with snot green on any part of skin the sticks out.

wash with thrakka green (don't use hair drier on the wash as it will blow it out of the recesses).

apply snot green over the highlighted areas about 5 more times. this is the end result. it looks better in real life than on this picture. you can do all sorts of fancy stuff with goblin green, glosses and the likes. but this is the simple way around it.