i have a janome sewing machine and janome makes a bobbin case specially set for free motion quilting - so instead of messing with the tension on the bobbin case, you just take it out and put the other one in. i don't know if other brands make this or not for their individual machines. but as everybody else said, it takes lots of practice. also i found something else that helps me - instead of adjusting your speed by how much pressure you put on the pedal with your foot, try setting the speed on your machine if you have that option, then you can push the pedal to the metal and only go as fast as you have that setting. this seems to work better for me.