I just made one for my sewing room! Mine is a 4'x4' piece of insulation board covered with 1 layer of batting and then an ivory flannel sheet. I secured the batting and flannel sheet to the back of the insulation board using duct tape. My husband mounted it on the wall for me. Fabric squares stay up well on their own, though I will sometimes secure with a pin especially if I am adding and moving squares around. I chose ivory flannel vs. white flannel as I had read other posts on this board and several folks stated that the white flannel was too bright...plus I already had an ivory flannel sheet I wasn't using!
Be sure to do a search on "sewing rooms" on this board. I got all kinds of great tips and idea's for my sewing room. Currently, I am working at folding/organizing my fabric stash. I can't begin to tell you how much fun I've had researching/planning/organizing my sewing room with all the great idea's from the generous quilters on this board.
Have fun!!!!