What I was told when I took my OBW class was to group the hexies by the predominant color -- white, yellow, pink, blue, then subgroup white/yellow, yellow/pink and pink/blue. Then arrange the hexies so that they flow diagonally starting with in one corner with the darkest (the most blue), blending into the blue/pink, to pink, blending into pink/yellow, to yellow, blending into yellow/white, and ending with the white in the opposite corner. Since I have never finished mine, you can take my advice as untried, but I have seen pictures of several OBWs done by another instructor, and this is what she did. I love your fabrics and colors. I look forward to seeing the finished quilt.