I pinned an old tablecloth with the flannel side out to the wall behind the door of my sewing room. Wish it was a little wider, but it serves the purpose well. I, also, covered a large piece of foamcore board with flannel and use it as a portable one or just for small projects. I can usually just press my quilt pieces to the tablecloth flannel on the wall with my hand and they stay there. If I'm hanging rows of blocks, I sometimes have to use a pin to keep them up. A design wall of any kind really helps to be able to step back and get a better idea of the whole picture.