I use a strip of Dr Sholls molefoam (the stuff you use on your feet) Cut a piece about 1/2" x about 2" and then stick that at exact 1/4" from the needle. Then glide the fabric along the molefoam. (I put a ruler on the machine bed, then slowly hand turn so the needle is at the 1/4" mark, then stick the foam along the side of the ruler)
You do have to pull the foam up every half hour or so and trim away where fuzz has accumulated along the edge the fabric slides on. Works like a charm.
Oh also make a mark on the machine with a permanent marker where the edge of the foam goes, that way do not have to measure each time.