Objective: Sew a secure, straight seam with proper backstitching and a clean pivoted corner on the Janome MC6650.
Three techniques turn threading into actual sewing: backstitching, seam allowance accuracy, and pivoting. Backstitching locks your thread at the start and end of a seam so it doesn't pull loose. On the MC6650, press and hold the reverse button (the U-turn arrow) to stitch backward; release to go forward. Seam allowance is the distance from the fabric raw edge to your stitching line. Most patterns and the home-goods projects you'll sell use a 5/8" allowance. The MC6650 has engraved and etched guide lines on the needle plate to the right of the needle, marked in inches and millimeters; you keep the fabric's raw edge lined up on the correct line and let the machine do the measuring. Keep a steady, moderate speed (the MC6650's speed-control slider helps you cap it) and guide the fabric lightly rather than pushing or pulling, which bends the needle and skews stitches. Pivoting lets you turn a corner without lifting the fabric: stop with the needle down in the fabric (press the needle up/down button so it ends down), lift the presser foot, rotate the fabric around the needle, lower the foot, and continue. The needle acts as the anchor, so the two seams meet in a crisp corner.
Try it: On a doubled 6"x6" scrap, draw a path that goes straight along one edge, turns 90 degrees at a corner, and continues. Set the speed slider to medium. Position the raw edge on the 5/8" guide line. Backstitch 3-4 stitches, sew forward keeping the edge on the line, stop about 5/8" from the corner with the needle down, lift the foot, pivot 90 degrees, lower the foot, sew to the end, and backstitch to finish. Inspect: the seam should be a consistent distance from the edge with a sharp corner and locked ends.