There are new and interesting colors that are only available in a tiny variety of parts. By using a neutral color you can maximize the effectiveness of those parts. Make the structure of your creation with a neutral color, then apply your rare colors as a fairing or as details. Apply colored parts to the neutral chassis shown.
About this creation
By using gray with a drab color like OD green, you can give the impression that the entire vehicle is OD green. This also works with the various "sand" variants of colors.
By using bright or bold fairings over gray you can make an effect of depth due to the gray receding and the brights popping out.
1. Use gray as a base color to experiment with different colors
2. Make a common chassis for color and shape experimentation.
More pictures are coming as I experiment and find good color combinations.