mad hopper-goblin

as u can see from this pic, my coloring skill is as horrible as it can get. and my shading is way off the chart. and the color i pick is terrible. but open to ideas to how it should be colored.

the mad hopper "goblin" is a heavy assault walker. armed with a dual 4x4 anti-air missile launcher, a medium linear cannon and a dual sm lazer.powerful, but the lack of speed and armor makes it vulnerable to enemy fire. due to amount of weapons installed on to it, it has lost the ability to jump-jet/cliff-jump across terrain but it capable of taking out a large group of enemy unit...provided the pilot gets the proper training to operate it well.