If you don't have a serger, you can zigzag the seams, just press lightly with either serged or zigzagged seams. Size 9 needle, Guterman polyester thread, an Elna machine, seven wedding dresses, 20 prom dresses, 15 bridesmaid dresses and never a puckered seam. Sometimes it's the machine, too. I borrowed a friend's machine because mine was busy elsewhere - mistake. The borrowed machine whose brand I won't mention wouldn't sew lace or satin.