Joining the diamonds into rows is easy.
Joining the rows so the points match perfectly is easy, too, if you just take a little extra time. First, determine which row will be on top when you join it to the section. With a ruler and a pencil, mark the sewing line, ¼” away from the raw edge. Now, here’s the trick. Align the raw edges of 2 rows, right sides together, matching the seams. Insert a pin where the seam and the sewing line intersect on the top row, through the seam on the bottom row. ( I eyeball that 1/4″ seam allowance on the bottom row.) “Hang” the pin – just leave it sticking straight through – and then insert pins through both layers on either side. Remove the hanging pin. Repeat this at every intersection. Sew on the marked line (very slowly over the pins). Bet you get it perfect almost every time…Jan Magee, The Quilt Life