I believe some people are just not able to handle randomness. I am one of those. I like Jeanne S's term "controlled scrappies." I find it totally impossible to operate without some kind of organizing principle. If I were you, I would develop an organizing principle to make it easier to put the quilt together. Whatever that principle is will depend on your personal taste in color and contrast. I sincerely doubt there is right way and wrong way; rather it depends solely on your likes and dislikes.