Mix some green and yellow paint and draw a band across the forehead, tapering to a point between the eyes. Add some spikes across the top.
Dab some green onto the spikes, then dab the colour down into the lighter band (but only slightly). In between each spike, draw another spike in green. With a thin brush, outline the first spikes you drew in dark green.
With a fresh brush and some white paint, draw seven tapered lines across the band, each one pointing towards a spike. Add some decorative dots between the eyes and either side of the eyes. Now paint some stars on the cheeks.