I think it is very important to pull the bobbin thread up before beginning a line of stitching to prevent thread nests on the back. I like to make the first down and up stitch near where I plan to start, raise the presser foot and pull the quilt away from the needle, and pull up the thread. Holding the two threads in my fingers re-position the needle in the ditch, then lower the presser foot. Then stitch away. Stitching in the ditch is a skill that has to be practiced whether you do it with that special sole plate on the newest Bernina walking feet or doing it with a regular foot. I like to do my stitch in the ditch with the open toed quilting foot-fre motion quilting. Stitch slowly.