There MUST be NO raw edges on the dress… pockets (pockets may have a pinked edge), hemlines (hemlines must be either serged and then turned up or turn the hem 1/4" and then turn up again) and seams MUST all have finished edges… not just a straight stitch but you must go further!!
1. French Seam
To make a french seam you first place WRONG sides of fabric together and stitch a narrow seam. Then flip your fabric with right sides together and stitch a seam (enclosing the first seam)
2. Serge or overlock the seam edge.
3. Straight stitch your seam and then go back and do a zig zag stitch between the straight stitch and edge of fabric.
More questions on Sewing with our guidelines…