There have been a lot of great new tools, ideas, and practices I've taken from the classes I've been taking over this past year. A formal art education is full of little nuances that you don't tend to think about when self educating. In the last week my eyes were opened to an extremely useful tool, a Color Wheel.
I've always known about 'The Color Wheel', but never truly given it much thought. I'd always just winged it and learned a little about how colors react with others, being sure to remember for the next time. I went through an entire year of classes, including a painting course, without the help of, what I'm quickly learning, is a tool that can save me a lot of time!
The wheel I picked up has a lot of little helpful pointers all over its surface. For canvas painting I find the above slots of color extremely helpful. It's a small quick reminder of how colors affect each other. This could come in very handy if you're in a pinch for a color and have to use what you have at hand instead or running out to the store for more paints.
The thing my hobby mind went nuts over was what I found hidden on the back of the wheel. The arrows, triangles and boxes overlapping each other made me immediately think of how much simpler color schemes can be if you use a color wheel. The complementary color arrows are the most immediately useful, pick your main color, and opposite will be a strong color to help the army stand out. But the others will be helpful as well in setting up other details of a models color scheme. The back even has a other helpful bits, showing two highlight tones of the hue as well as a shade that can easily be translated into washes and stage highlights.
You don't need to go out and purchase a color wheel, although they won't break the bank. There are a lot of references around the net that you can find with just a quick search. One I found with just a few seconds of looking is called the Color Scheme Designer and does a lot of what I mentioned here. For creating army schemes I think that program is easily at the top of my bookmark list and is flexible enough for you to play with various options and see how they present with each other.