I would also like to mention, check your rulers and cutting mat for accuracy of the markings. Not all mats and rulers are accurate. When you cut your pieces do you place your ruler mark up to or on the measurement mark you are going to cut. It should be on the mark not up to it. I hope this is clear. As mentioned thread can make a difference. I buy Guetermann (sp) cone cotton thread from Joanns when it's on sale. It's online only. It's a very fine, strong thread and no lint.