Objective: Combine seam finishing, zipper insertion, topstitching, and boxed corners into one planned workflow to produce a saleable lined zippered pouch.
Making a sellable item is less about any single technique and more about ordering techniques so each one doesn't fight the next. The pro habit is to plan the whole sequence before you touch the pedal, then batch settings changes. On the MC6650, use its memorized settings and the needle up/down button (set needle-down for pivoting) and the thread cutter to move cleanly between steps. A smart build order for a lined zip pouch is: (1) finish any raw edges that will be exposed inside with a zigzag or the overcast stitch, (2) install the zipper between outer and lining using the zipper foot, pressing and topstitching close to the teeth for a crisp professional edge, (3) open the zipper halfway so you can turn the pouch later, (4) sew outer-to-outer and lining-to-lining in one continuous seam, leaving a turning gap in the lining, (5) box the bottom corners by flattening each corner into a triangle and stitching across to give the pouch depth, (6) turn, close the gap, and edge-stitch. Group your setting changes: do all straight-stitch construction with one setup, switch to zipper foot once, and reserve topstitching (often straight stitch, length 3.0) as a single final pass. Always backstitch or use the lock-stitch at stress points like zipper ends and corners.
Try it: Build one lined zippered pouch (roughly 8x6 in) on the MC6650 following the order above. Before sewing, write your six-step sequence on paper with the exact machine setting beside each step (foot, stitch, length). Finish exposed edges, insert the zipper with the zipper foot and topstitch at length 3.0, sew outer and lining in a continuous seam leaving a 3-inch lining gap, box all four corners to about 1.5 in, turn through the zipper and gap, then edge-stitch the opening closed. Inspect: zipper lies flat, corners are symmetrical, no raw edges show.