Objective: Inspect, stress-test, and finish your completed signature item so it meets a paying customer's standard.
A hobby item and a saleable item differ in the details that survive use and scrutiny. Testing and polishing is the gatekeeping stage between 'done sewing' and 'ready to sell.' Work through three layers. First, structural testing: tug firmly on seams, straps, closures, and stress points (corners, pocket openings, zipper ends). On the MC6650, high-stress seams should have been backstitched or bar-tacked; if a seam opens or puckers under pull, re-sew and reinforce. Check that your thread tension produced balanced stitches on both sides—no loops underneath, no top thread being pulled through. Second, functional testing: zip the zipper ten times, button and unbutton, turn the bag inside out and back, wash a swatch of the same fabric to confirm it won't shrink or bleed. Third, cosmetic polishing: trim every thread tail, clip curves and corners so they lie flat, and press. Pressing is the single biggest 'professional' signal—use steam and a pressing cloth, set seams flat, and press from the wrong side to avoid shine. Finally, run a written quality checklist so you evaluate the same points on every unit you make, which is what keeps a home business consistent.
Example: Say your signature item is a lined zippered pouch. You tug the side seams—solid. You pull the zipper end tab and notice the stitching there is single-pass; it feels weak, so you return to the MC6650, select a bar-tack or dense zigzag, and reinforce both zipper ends. You zip it 10 times: smooth. You find three thread tails inside and a corner that bunches, so you clip the seam allowance at the corner and re-turn it. Finally you press: set the lining seam, press the exterior from the wrong side with a cloth, and the pouch now holds a crisp, flat shape ready to photograph and sell.
Try it: Take your completed capstone item and run the full three-layer test. Write a 6-point quality checklist specific to your item (e.g., 'all stress seams backstitched/bar-tacked,' 'zipper operates 10x,' 'no visible thread tails,' 'corners clipped and flat,' 'tension balanced top and bottom,' 'pressed with cloth'). Physically check each point, fix any failures on the machine, then press the finished piece and mark each checklist item pass/fail.