1. Prepare and Sew the Primary Seam

• Place fabric pieces right sides together and align raw edges.
• Pin or clip along the seam line.
• Sew the seam using your pattern’s seam allowance (commonly 1/2 in or 5/8 in), backstitching at both ends.
• Remove pins as you sew.

2. Press the Seam

• Press the seam flat as sewn to set the stitches.
• Press the seam allowances open (for a flat-felled or decorative seam) or press both allowances to one side (most common for double stitched seams on jeans and bags).
• Use steam if your fabric allows for crisper pressing.

3. Choose Your Double Stitch Configuration

• Option A (Most Common): Both rows of topstitching on the right side, one close to the seam line and one farther away, with seam allowances pressed to one side underneath.
• Option B (Flat-Felled Look): One row of stitching on each side of the seam line with seam allowances pressed open underneath for symmetrical topstitching.
• Option C (Reinforced Seam): One row directly on the seam line and one row 1/8–1/4 in away on the seam allowance side.

4. Mark Your Stitch Lines (Optional but Recommended for Beginners)

• Use a seam gauge, quilting ruler, or fabric marking tool to measure and mark parallel lines where you’ll topstitch.
• Common spacing: First row 1/8 in from seam line, second row 1/4 in from first row (total 3/8 in from seam line).
• For decorative denim-style stitching, space rows 1/4–3/8 in apart.

5. Attach Edge Stitching or Guide Foot (Optional)

• If using an edge stitching foot, position the guide blade along the seam or fabric fold to maintain consistent spacing.
• Adjust the needle position if your machine allows for precise placement of the first row.
• A walking foot helps feed thick layers evenly and prevents shifting.

6. Sew the First Row of Topstitching

• With the right side facing up, position fabric under the presser foot so the needle will stitch parallel to and close to the seam line (commonly 1/8 in away).
• Lower the presser foot and needle into the fabric at the seam’s beginning.
• Backstitch 3–4 stitches to lock the thread.
• Sew steadily along the marked or guided line, keeping your eyes on the seam edge or guide rather than the needle.
• Backstitch at the end and trim thread tails.

7. Sew the Second Row of Topstitching

• Reposition the fabric so the needle will stitch the second parallel row at your chosen distance from the first row (commonly 1/4–3/8 in).
• Use the edge of the presser foot, a seam guide, or your marked line to maintain consistent spacing.
• Backstitch at the beginning, sew the full length, and backstitch at the end.
• Trim thread tails close to the fabric.

8. Press the Finished Seam

• Press the double stitched seam from the right side to flatten the topstitching and blend the threads into the fabric.
• Use a pressing cloth if working with delicate or synthetic fabrics to avoid shine or melting.

9. Troubleshooting Common Issues

• Uneven rows: Use an edge stitching foot or mark guidelines; practice maintaining a steady seam guide reference point.
• Puckering: Reduce presser foot pressure, use a walking foot, or slightly loosen upper tension.
• Thread breaks: Switch to topstitching or jeans needle; check that thread is feeding smoothly and isn’t old or brittle.
• Skipped stitches: Use a sharp or ballpoint needle appropriate to your fabric type; slow down on thick layers.
• Visible bobbin thread on top: Adjust upper tension slightly looser, especially when using topstitching thread.