On my latest anim I did, for like sunray lighting I turned the yellow opticity to around 20%, keep on stroking along to mix the coloring and then you got some lighting (you can do the same with other colors too)
I also highly recommend blending white and your color of choice for the lighting
before you shade decide where you want the light source to be coming from
then insread of shading on the opposite side with dark color
shade on the side the light source is coming from with a light color that isn't white (yellow,pink, and light blue are good colors to use)