I choose my theme fabric first. Then I select 2 colors from it, 1 dominant, 1 supportive. I don't consider the background a color.
Next, working on 1 color at a time, I select variations of the color; light, medium, dark. I place that color on the theme fabric and see how it impacts the fabric. I'm looking for that spark, that it doesn't create a matchy-matchy look, but accents the fabric.
Now, work with color 2 the same way, & continue with any other colors you have selected.
Once I have choosen all the colors, I lay the theme fabric out and place all my colors on the fabric and stand back & look at it for impact. Sometimes I hand them on my quilt wall and look at them for a couple of days & in different light(night,day,indirect).
Here is an example of one I am working on now.
theme fabric
[ATTACH=CONFIG]196461[/ATTACH]
supporting backrgound
[ATTACH=CONFIG]196464[/ATTACH]
still considering this, maybe a small amount
[ATTACH=CONFIG]196465[/ATTACH]