Try a different or new needle. Remove all thread from the machine and rethread it from scratch. Open all service panels and clean out all lint. If the manual directs you to oil the machine, do so according to the manufacturer’s instructions using quality sewing machine oil. (Do not use standard household oils or automotive oils. Only sewing machine oil should be used on a sewing machine.) Use a better quality thread. Adjust the thread tension. Hold onto the loose ends of both the upper and bobbin threads as you begin the seam. Do not fold, spindle, or mutilate. Do not run with scissors. Do not play with fire. Where has that finger been?