Piecing Curves Perfectly
To make it easier to ease fabric pieces together when pinning curves, hold the pieces with the convex curve on top of the concave-edge piece (trimmed triangle-square).
After pinning, slowly sew together pieces, using a slightly longer than normal stitch length, which helps ease the fabric layers together.
Some quilters prefer to clip curved seams. Clip into seam allowance of the concave edge as needed, but do not cut into or beyond the seam line. Do not clip the convex edge.