I usually face my wall hangings and let the design of the wall hanging go all the way to the edge. This is different than birthing where you sew right sides together and then turn then quilt. With facing you quilt as you would with a binding but then as a last step put on a facing instead of a binding. There are a number of methods to do it but here is a tutorial to give you an idea.
http://thesillyboodilly.blogspot.com...y-to-face.html