with your feed dogs down, don't adjust your tension, the speed with which you move your fabric determines the length of your stitches - sew fast, move slow.
also about stippling where the binding will be going: a longarm quilter told me to do this: after squaring up your quilt, go around the edges with a narrow but long zia zag stitch very close to the edge, then sew the binding over that. works great - makes the binding easier to attach, and assures that any stippling stitches that were cut won't ravel and also makes you feel better about it staying together better when laundered.