Cut two squares of fabric that measure 12 inches on each side using a pair of scissors. Use a beach-themed print for both squares or make one square with a beach print and the other with a cool pale blue reminiscent of the ocean.
Lay the two squares of fabric together, pattern side in.
Sew around the edge of the squares using a running stitch or a back stitch set 1/4 inch from the edge of the fabric, binding the squares together. Leave a 4-inch gap along one side where you can stuff the pillow. Sew by hand using a size 7 sewing needle or smaller and sewing thread.
Turn the pillow inside out through the gap.
Stuff the pillow using fiber fill. Fiber fill is widely available at craft and fabric stores. A 20-ounce bag of fiberfill is more than enough for a 12-inch square pillow. Stuff the pillow as lightly or as heavily as you prefer. The more fiberfill you put in, the puffier the pillow looks.
Turn the raw edges of the gap into the pillow and sew it shut.