Sometimes I use more than three colors to paint a miniature starship. For example, with the insectoid Entomolians I wanted to go with an iridescent look, like the carapace of a beetle. It's the same concept as
how I paint my Terran ships, but I enjoyed applying additional colors.
Again, I start with a flat black coat of spray paint for a primer:
Then, Americana Blue (or Blue Violet) on the rear half and Anita's Fathom Green for the front:
On top of those go the Folk Art Metallic Periwinkle (back) and Metallic Peridot (front). It's OK if the colors overlap a little in the middle; that just smooths out the blend and makes it look organic:
Next, Metallic Emerald Green (from Folk Art) on top of the rear colors. Again, there are no hard borders for any color on these ships:
And Metallic Plum in front--although I might have overdone it a little on this one:
Finally, I highlight the bridge with successive drybrushes of Yellow Ochre, Bright Yellow, and Metallic Inca Gold (all Folk Art except the Bright Yellow, which is Americana):
As seen below, this paint scheme gives the bugs a colorful look without a painstaking effort on my part, and I find it enjoyable to use a greater number of colors:
How do you paint your insectoid aliens' starships?