Use a water-disolvable marker to plan out your circuit traces.

You may need to adjust the tension on your machine. Experiment on a scrap piece of fabric and examine the balance between the conductive and regular thread. Adjust the tension and experiment again until you are satisfied.

Machine stitch your circuit.

Leave long tails of conductive thread at the ends of your stitching lines in case you need to pick them up with a hand sewing needle and connect to other components.

Spritz away the markings with water. Be sure to let the fabric completely dry before powering up your circuit.