A seam is a line of stitching that joins two or more pieces of fabric. The following are some of the most common seam types used in dress marking: Plain Seam: This is the most basic type of seam where two fabric edges are aligned and stitched together with a straight stitch. It's often used for lightweight and medium-weight fabrics. Double-Stitched Seam: This is equivalent to sewing two stitches down the fabric pieces to attach them for extra reinforcement. Top-stitch: This is when you sew a plain seam and press the seam allowance on one side before making a top stitch on the right side of the fabric. Here's a video tutorial on how to top stitch! French Seam: A French seam is a neat and enclosed seam that encases the raw edges within the seam allowance. It's commonly used for lightweight fabrics and creates a clean and finished look on the inside of the garment. Flat-felled Seam: It is a double-stitched, closed seam that is strong enough for tougher fabrics. The stitches are made to press the seam flat down and to make it appear less bulky. Watch the video tutorial on how to sew a flat-felled seam for fabrics of different weights. Welt Seam: A Welt seam is a strong seam that is similar to a flat-felled seam but exposes the raw edges of the fabric. After one stitch is made to sew the layers together, the top piece of fabric is folded, and another stitch is made to hold the raw edge down. Hem Tape: This tape is made of an adhesive that melts and glues two layers of fabric together. It is not permanent and will only last a few washes, so use it with caution.