It takes practice & adjusting to get it just right ... not all machines are the same! My rule of thumb - if the thread is loose on the bottom, tighten the top tension SLIGHTLY!! If the thread is loose on top, loosen the top tension. You rarely need to adjust the bobbin case tension. Use the same thread top & bobbin and a brand new needle. Take your time! Practice on sandwiches of the same fabrics as your quilt. Concentrate on making even stitches and don't get in a hurry. I like to use the little quilting gloves that have the grips on the palms to move my fabric. You'll get it ... and you'll be very happy!