Made string quilts at a local guild event and had one woman who couldn't put random fabrics together. We mixed them up in a brown bag and told her she had to use whatever she pulled out. She complained and fretted for the first block. When she saw it trimmed, she admitted how much fun and freeing that block had been. And she tried a second block. After that she never looked back. Just grabbed and sewed. Maybe you could just try a block or two in this fashion and see if loosens your grip on order:-) Also having the center strip stay constant helps give it some order and forms a secondary pattern when all blocks are sewn together.