1. Prepare Pattern Pieces and Transfer Markings

• Cut out all bodice or dress pieces according to your pattern, including center front, side front, center back, and side back panels.
• Transfer all notches, balance marks, bust apex marks, and waist marks from pattern to fabric using tailor’s tacks, chalk, or tracing paper.
• Note which edges are convex (outward curving, usually center panels) and concave (inward curving, usually side panels).

2. Interface and Staystitch

• Apply interfacing to facings or bodice sections as directed by your pattern.
• Staystitch both princess seam edges on each piece at 1/2 in (or slightly inside the seamline) from raw edge to stabilize and prevent stretching.
• Staystitch directionally: stitch from wide end to narrow end or follow pattern guidance.

3. Pin the Seam

• Place the concave (inward-curving) piece on top and the convex (outward-curving) piece on the bottom, right sides together.
• Match and pin at all notches and balance marks first, inserting pins perpendicular to the seamline.
• Working between notches, gently ease and pin the concave edge to the convex edge, matching seamlines (not cut edges).
• The top layer will have slight excess that eases around the curve; distribute this evenly without pleats or tucks.
• Use plenty of pins (every 1–2 in) for a smooth result.

4. Sew the Princess Seam

• With the concave piece on top, sew along the seamline at your pattern’s seam allowance (commonly 5/8 in), removing pins as you approach them.
• Keep the layers aligned and let the feed dogs ease the top layer naturally; do not stretch either layer.
• Use a shorter stitch length (2.0 mm) for better curve control.
• Backstitch at both ends.
• Check the right side for smooth curves and no puckers; adjust and re-stitch if needed.

5. Press the Seam Flat

• Without opening the seam, press the stitching line flat to set the stitches and relax the thread.
• This step helps the seam lie smoothly before pressing open or to one side.

6. Press the Seam Open or to One Side

• Open the seam allowances and press over a tailor’s ham or curved pressing surface to maintain the garment’s shape.
• If your pattern directs pressing to one side (common for bust shaping or unlined garments), press both allowances toward the side panel or as instructed.
• Use steam and a press cloth if working with delicate fabrics.
• Avoid flattening the curve by pressing on a flat surface; the ham preserves the three-dimensional shape.

7. Clip Curves if Necessary

• On the concave (inward-curving) side, clip small notches perpendicular to the stitching line if the seam puckers or won’t lie flat.
• Clip to within 1/8 in of stitching, spacing clips every 1–2 in along the tightest part of the curve.
• Do not clip the convex side; it needs no release.
• Press again gently after clipping to encourage the seam to open smoothly.

8. Grade Seam Allowances if Needed

• If the garment is unlined or seam allowances will be visible, trim and grade to reduce bulk.
• Trim the under layer (closest to body) to 1/4 in and leave the upper layer at 3/8 in to create a graduated edge.
• Skip grading if the garment will be lined or if fabric is lightweight.

9. Finish Seam Allowances

• Finish raw edges with a serger, zigzag stitch, or pinking shears to prevent fraying.
• If pressed open, finish each allowance separately; if pressed to one side, finish together as one.

10. Repeat for All Princess Seams

• Complete the remaining princess seams on the bodice front and back using the same method.
• Press each seam carefully over the ham to preserve shaping.

11. Baste and Fit

• Before final construction, hand-baste or machine-baste side seams and shoulder seams, then try on the garment.
• Check fit at bust, waist, and hip; adjust princess seam placement or take in/let out as needed.
• Once satisfied, remove basting and proceed with final construction per your pattern.

12. Troubleshooting Common Issues

• Puckering at curves: Ensure you sewed with the concave piece on top; re-press over a ham and clip curves if needed.
• Seam doesn’t lie flat: Check that notches were matched accurately and that you eased rather than stretched the fabric.
• Wavy seam on the right side: Stitching may have stretched the fabric; re-staystitch and sew with a walking foot or less tension.
• Bust point misaligned: Verify pattern bust apex marks were transferred and matched during pinning; adjust for full or small bust if needed.