Simplest method: Layer, wash, drybrush.
Layer the base color down, then wash the entire thing down darker (in your case, use Biel-tan green or something similar). Then take a lighter color and slowly work up highlights through drybrushing across the tops of the folds. I'd say go with Loren Forest and go up from there to paler colors. Option B is to go bright on the colors (Warpstone, etc).
I've got some models, but the only pics I have
atm really suck.
Here, we have Loren Forest -> Biel-Tan Green (wash) -> Straken Green (drybrush)