Objective: Practice controlled straight lines, corner pivots, and curves on scrap fabric so that your seams become accurate and repeatable before you sew real projects.
Sewing well is muscle memory built from a few core skills: feeding fabric at a steady pace, keeping a consistent seam allowance, pivoting cleanly at corners, and steering around curves. On the Janome MC6650, the needle plate has engraved guide lines marked in inches (1/4, 3/8, 1/2, 5/8) and in millimeters; line the raw edge of your fabric against the 5/8" line to hold a standard garment seam allowance. Let the machine's feed dogs pull the fabric—your job is only to guide, not push or pull, which prevents bent needles and wavy seams. Set a moderate speed using the slide speed control so you have time to react. For corners, stop with the needle DOWN (press the needle up/down button or the dedicated pivot), lift the presser foot, rotate the fabric 90 degrees around the needle, lower the foot, and continue. For curves, sew slowly and make tiny steering corrections rather than one big turn, keeping your eye on the guide line and not on the needle itself. Backstitch two or three stitches at the start and end of each line to lock the thread so your practice seams don't unravel.
Example: Take a 6"x6" square of woven cotton scrap. Mark four lines with a ruler and fabric pen: two straight lines 1" apart, one right-angle corner path, and one gentle C-shaped curve. Set straight stitch, length 2.5, speed to about one-third. Place the fabric edge on the 5/8" guide, backstitch, then sew the first straight line at steady speed, letting the feed dogs do the work—you should finish with an even, non-wavy line. At the corner path, sew to the mark, press the needle-down button, lift the foot, rotate exactly 90 degrees, lower the foot, and continue; the stitches should meet in a sharp point. For the curve, slow down and nudge the fabric in small increments, keeping even spacing. Backstitch to finish each line.
Try it: Using a scrap of medium-weight woven cotton, sew five exercises: (1) three parallel straight lines using the 5/8" guide, (2) one square outline requiring four pivots, (3) one wavy S-curve, each with backstitching at both ends. Inspect your work: measure that the parallel lines stay roughly 5/8" from the edge, check that corners form crisp points, and confirm the curve has no sharp kinks.