Write an article based on this "Fold the 1⁄2 yard (0.5 m) fabric in half, right sides facing each other, and stitch the long edges of the rectangle together with a 1⁄2 inch (1.3 cm) seam. Turn the blanket right-side out through the open side of the pillow pocket. Sew a 1/4 inch seam to close the open edge only; do not stitch the way around the pocket."
Make sure the edges are lined up and pinned before you begin stitching. You are making a mini-version of the main blanket, only without the batting.  One side of the rectangle should still be open so you can flip the fabric right-side out. Snip off the corners with scissors. This gives your pocket nice, sharp edges. Again, reach into the opening and use a pencil to push out the corners.  Press the fabric with a warm iron, locking the stitches and smoothing out any wrinkles. Fold the open side of the rectangle so its is even with the edge of the rest of the pillow pocket. Use the iron to crease the fold and pin the opening closed. You will be sewing these edges later, when you attach them to the large blanket.