You must be EXTREMELY careful to get exact 1/4" seams on these stars, and with all these pieces being cut on the diagonal, do not stretch the fabric. You will now have to re-sew some of the seams until the piece lies flat, and then sew 4 pieces together, and then the other 4 pieces together, and then sew the 2 half-stars together, matching up the center seams. Press all of the seams OPEN on this, as it helps reduce the bulk.
I recently did a Queen sized lone star, and I had good luck. You MUST be extremely careful with your seams and handling the fabric.
PM me if you need more help. :-)
Here's the quilt I did:
http://www.quiltingboard.com/t-79225-1.htm