You'll need to experiment with your machine tension on scraps of the same fabric and batting you intend to use for FMQ. Usually, the upper tension needs to be loosened some to prevent bobbin thread from being pulled to the top of the fabric, but that too is a matter of testing until it is where you like it. The stitch length is not important as long as you drop the feed dogs so it will not attempt to pull the fabric or create any interference with your manually moving the fabric. (A silicon Slider is nice to have--you can find them on the internet. It creates a slick surface so your fabric will move easily.) You will manually determine the stitch length because you will be manipulating the fabric. Also, be sure to use a darning foot or free motion quilting foot so there is space between the foot and the needle plate to move the fabric. Install a brand new sharp needle. Some people like to use Microtex, embroidery or top stitch needles. Beyond that, Practice, Practice, Practice! Practice making smooth movements. If you can't practice on the machine, get a cheap white board and practice drawing your designs on the board. You can erase and do it over and over, even while you're sitting watching your favorite TV show. If you like a particular design, take a photo of it with your cell phone so you can refer to it later.

...