I think you mean stitch length, and you can only control this by your quilting motion, going quicker seems to make stitching easier, make certain your feed dogs are down, so you don't break any needles, and practice is your best tip on getting your stitches more uniform in length. I do a couple of sandwichs of fabric, batt and backing, and if making those into potholders, put in a layer of insulbright and put binding around the eges.