I was doing a string star block and was frustrated because I could not get the "Y" seams to be perfect. I then read on the internet to first sew the stem of the "Y". Then put a pin into the triangle where the "Y" seam and triangle patch come together and sew from the outside edge into the stem. Place your needle down where the two seams meet. Turn the fabric and sew a couple of stitches. DO NOT BACKSTITCH as some machines take a stitch before they start back. Repeat on the other side. I found that this method worked perfectly for me. Hope this is clear.