I paper pieced all of my sections INCLUDING the stand alone squares. For those I did a basting stitch around the outside between the edge and the start of the seam allowance. I figured that by sewing it to paper I could follow the lines and know precisely where to stop sewing. When I completed my first Y-seam and it looked beautiful I did a happy dance!!!! (The picture also shows how I basted the square onto paper.)
I'm so ridiculously proud of my block that I've been joking that I need to frame it!