I like to find a dowel or curtain rod of the right diameter to slide right into a cup hook. Then the quilt lies quite close to the wall and flat.
My other method is to sew a sleeve and run an inexpensive strip of firring thorugh it(coated in polyurythene to protect the fabric). Tiny little holes drilled in the ends of the firring strip and you can use very small nails to attach to the wall, with no visible means of hanging, which is my preferred style in our house.
RST