I always think if I like the fabrics together, then it works! After all, it's my quilt and I can do what I want. It usually works great, but I leave the fabrics spread out on my cutting table for a few days, just looking at them now and then. If I see one glaring at me, I'll pull it and replace it with another. By being able to look at the fabric, I can tell if I'm going to like the finished quilt.