I answered this question in the LAF forum some months ago:
This is one of my unit of orcs (well the only painted one).
They're all from Kev Adams, there is foundry, oop citadel, harlequin, renegades and heartbreaker miniatures. It was a pain to gather all of them but I did it :).
So basically, I am using some goblin green, then I used a green wash. After that I lay down two brighter green: scorpion green, then a green goblin mixed with a lot of yellow. I only do the angle with the second one.
And finally, a little close up on the standard bearer:
With the evil sunz banner :)
Until next time where I'm planning to show you some real new stuffs.