Joining two pieces of fabric together in a perfect straight seam is essential for almost every sewing project.
-With the right (front) sides of the fabric together, pin the fabric where the seam will be; pins should be perpendicular to the cut fabric edge.
-The seam allowance is the distance between the edge of the fabric and the seam. Usually a seam allowance of 5/8 inch is called for; position the fabric accordingly (on many machines, a marking on the throat plate helps you guide the fabric and maintain your seam allowance).
-Back-stitch at the start of a seam to keep it from unraveling: With the presser foot raised, position the fabric so the needle is about 1/2 inch from the fabric's top edge. Lower the presser foot, and reverse-stitch to the top edge, then stitch forward to make the seam.
-Machines can stitch over pins (left), but it's a good idea to remove them as you go. Guide the fabric with your hands as you sew. When you reach the end, reverse-stitch again, about 1/2 inch.
-Press the seam open so the seam allowance lies flat against the fabric.
-After sewing a curved seam, such as a neckline [image 2 above], clip small notches in the seam allowance so the fabric lies flat when it's turned right side out.
Seam finishes Keep fabric from unraveling and make a seam more durable. Here are two simple ways to finish a seam [See image 3 above.]
-Zigzag-stitch close to the edges, then trim as close to the stitching as possible (left seam).
-Straight-stitch about 1/4 inch from the edges, then trim with pinking shears (right seam).