Experiment with the grass. Draw out the points of light and shade in a simple manner, experiment with a way to get nice grass texture, draw the simple forms of the stuff he's got growing on the helmet and then fill in the rest with grass texture. Something like that.
Don't forget the mossy stuff on his arms!
Coming along well, don't give up! Also you could increase the saturation on one of the green colours in the ramp, to get that nice 'light shining through grass' glowy effect. Preferrably one of the three brightest greens. Experiment!