You know what I did with my daughter (college aged) before I made her quilt and it worked well? I heard that Lowe's had paint swatches that have four accent colors that go with the main color (not necessarily in the same color family). I had her go with me to pick some up and made a note in my mind of the ones she seemed to really like and then used that for my color palette for her quilt. It was the perfect solution for me - maybe you can try that.