Do you have a blind hem (5) or an edgestitch (10) foot? Both can be used to stitch in the ditch. I also have used my Janome ditch foot to quilt a marked cross hatch. Warning: on my machine, the foot requires feed dogs down, so I need to loosen the presser foot pressure, go slowly and be careful. Other than that, Feline Fanatic is right: to FMQ straight lines, you either need to be very good at moving the quilt in a straight line or add the ruler foot.