Hello Richard,
The first consideration in color mixing the temperature of the light source. An understanding of this will often yield the best direction to go in as far as which colors to mix for what.
Any time I get a question about color, especially color mixtures, I always ask if they have done their color charts yet. I can usually tell from the questions whether someone has done their charts. The question would have been answered in the doing of them. Here is a link to detailed instruction on how to do the color charts for anyone interested.
http://claytonjbeckiii.com/Instructional2.html