I have a simple method to paint ork flesh. I only use 4 paints and it is fairly easy to batch paint using this method, which is a good thing when you use the green tide tactic and have loads of boyz to paint!
The first stage is to apply Waaagh flesh using a basecoat brush.
The next step is to apply the wash biel tan green using a wash brush.
Then using the standard brush apply warboss green to the raised areas of the flesh.
The final stage is to use the detail brush to apply skarsnik green.
Better pictures will follow to demonstrate this better, I will also be adding more detailed guides on how to paint each of the clans I currently collect.