I actually browse through pictures of quilts already made on the Quilt Gallery on this board. It gives me a chance to look at different colors together and different patterns. Sometimes I just google something like Purple Quilts. I get lots of ideas this way.
And I have found that I actually prefer fewer colors in a quilt than many quilters. I love two fabric quilts, and I love quilts that have several shades of the same color or of two colors.
So, mainly I look at other quilts and decide what I prefer. Hope this helps.
Dina