I quilted several log cabins on my DSM before getting a longarm. I quilted them in sections, so I didn't have so much bulk going under the machine's arm. I stabilized the top by SITD in all the seams where the blocks joined, then started doing all those log cabin seams. I would start at one end, make some close together stitches or back stitch when that seam ended, then move down to where the next seam started up, again make some close together stitches or backstitch and continue. I used the walking foot. Practice helps you get into the seam, but if you're not quite in it don't worry - no one will notice anyway, and when the quilt is washed the seams will be even less noticeable. Another option is to do a wavy line across the seam line, or quilt "next to" the seam, but I prefer SITD.