Pinning Is the Secret
When you want the seam lines in patchwork pieces to line up perfectly, first pin the pieces together with extra-fine pins. With right sides together, pin one piece to another unit, aligning raw edges. Match seams by pushing a pin through both layers to check alignment.
Match up seams of pieced units and place a pin diagonally through the pieces, catching both seam allowances.
To prevent damage to your machine or injury to yourself, avoid sewing over pins. When you’re sewing together long strips without seams, there’s no need to pin before assembling.