If you want your fabric to be absolutely smooth on the wall switch and you are not trying for any added texture, you can use varnish. Varnish a clean wall plate,put the fabric on the wall plate, varnish the fabric, let the whole thing dry at least 24 hours. When it is dry either trim the fabric at the edge and varnish it again or fold the edge under, trim and varnish. The varnish will be your glue and waterproof finish. It's easier if you use varnish that cleans up with soap and water but not necessary. If you haven't done much varnishing, try it out on anything that is throw away. This is an older, cheaper version of the craft decopage. The secret to using varnish is to use very FEW brush stokes. Too many strokes will turn it cloudy.