As with cutting, avoid using pins on the fabric as it’ll leave holes. Instead hold pieces together firmly in your hands as you sew.
Use a sharp needle in the smallest size possible that is able to stitch the fabric without skipping.
Join the two sides of the front cover if doing a similar color block design. Match RIGHT sides together and stitch with a ½” seam allowance.
Sandwich the fabric in between layer of tissue paper and sew. Hold the fabric firmly to avoid differential stretch as you sew.
Lay the FRONT and BACK pieces RIGHT sides together and sew along all three edges with a ½” seam allowance.
Tear off the paper after sewing.
Sew the final edge partially closed leaving enough of a gap to squeeze the pillow insert into.
Before turning the piece right side out, consider adding a waterproof sealant to the seams to avoid water seeping through.
Clip the corners and turn the pillow cover right side out, poking the corners out with a pair of tweezers and then stuff the pillow insert inside.
Lastly, sew the opening closed with an edge stitch.