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!

It takes time and a lot of practice. I'm also teaching myself to FMQ and have been doing it for about a year and it does get easier the more you do.

Pictures would help us to help you. It sounds like you may have a tension adjustment problem.

Before I start FMQing, I always FMQ a few straight lines on a sample sandwich the same as my quilt so that I can adjust the tension. Part of the problem might also be inconsistency in speed that you are moving the fabric; I experienced that also when I was starting out, and the problem mysteriously "disappeared" as I got better at controling and coordinating the movement of my fabric and the speed of my machine.

Keep practicing and eventually you'll get better at it.:thumbup: