try an exercise like the one below. I don't have a natural ability for color
theory. So I've spent time playing with fabric trying to attain some skill
with color. Working with a monochromatic palette makes it easier to
understand.
For this project I chose a quilt block that had three colors. I replaced the colors
with Grey Scale equivalents; the lightest color becomes white, the darkest color
becomes black and the remaining color becomes grey. Now chose a color to
work with and find three values in that color, light medium and dark. Make
a few samples to see the results of your selection. Don't forget to play
with the borders.
The proportion of the border width in relation to the block size can make or
break a design. I'll talk about proportions another time.