I started with a 18" square pillow, that was previously covered with a very sad looking, sage green suede. The black damask would definitely be an upgrade. Despite the fact that this 100% cotton fabric said to "dry clean," I washed and dried it as I would any other fabric--no harm was done. I wanted to make sure that if the cover ever was dirty enough to wash, I could simply throw it in the wash.
Next I measured and cut an 18" square piece of fabric and set it aside--just one piece, this is the front. Then I cut a second piece (the back), allowing an extra four inches so it measured 18" by 22". This piece I cut in half, leaving me with two pieces each 18" by 11.
I folded over and sewed down the edge of these two smaller pieces.
I Then overlapped them and pinned them right-sides to the 18" by 18" piece of fabric, making sure all the edges matched, and the pattern was pointing in the same direction. The two back pieces overlapped by about two inches.
I sewed all four sides with a 5/8 inch seam allowance, turned it inside out, stuffed in the stuffing and....Voila! A new pillow!