I like to use a three color trim scheme whenever possible. Have had good luck with yellow/red/dark blue or white/red/dk blue. For a fuselage, I might put the darkest color on the bottom (say dark blue) yellow on the side and red on top. The wing might be blue along the LE, yellow in the center and red along the TE. The bottom of the wing might be red along LE and blue/white checkerboard or stripe on the bottom. My feeling is to create as much contrast between the top of the plane and the bottom of the plane as possible. Many ARF's especially trainer use white on the fuse, white on the bottom of the wing and a couple of stripes on the top of the wing. With this trim scheme I have a very hard time distinguishing the top from the bottom of the plane. This can be disasterous if your not careful. Colors that are closely related tend to blend together and are hard to see, especially on smaller planes. I've noticed that as I have gotten older it is harder for me to see colors at far distance. This is one of the reasons I like the bigger planes, they are so much easier to see. I make sketches of the plane and try out different color schemes using magic markers to color in the sketches.