Just make certain the border are the same length on opposite sides. It sounds easy, but it's not. If there is too much border, long may they wave. Of course if it was a quilt instead a wall hanging, I would just say, throw it on the floor. Which is where mine seem to end up. They are seldom folded. I have helped wall hangings straighten by hanging a rod on the bottom also. It "pulls" it down by adding weight and keeping it semi flat.