The only problem with facings is that once a piece has been densely quilted, it's hard to turn back the edge and make it lie nice and flat. You have the hefty batting, plus a drapery-weight backing, plus the pieced quilt top itself, all held together with lots of stitching, and that sucker just doesn't want to fold, let alone stay there after you stop pinching it.
I've tried various ways to get a flatter, neater edge. Pressing is useful, providing you can establish a neat fold in the first place. Understitching can also help; that's a technique borrowed from garment sewing where you stitch through the facing, plus the two seam allowances, just barely inside the seamline that attached the facing to the quilt.
Probably my best insight was to stitch the facing a half-inch in from the edge, not a quarter-inch. Even paper, which is generally easy to fold in perfectly straight lines, will misbehave if you turn back only a quarter-inch, and fabric is inherently much more difficult to control.
But even with wider margins, the edges resist arrest. So my second-best insight is to topstitch the margins, so to speak, and make sure there's no way for the quilt package to spring back toward its original flat contour. With some quilting designs, of course, you don't want a row of topstitching around the edge, but most of the time I like to quilt in a grid pattern and that works perfectly for this technique.
So here's my plan: as I get toward the edges of my quilt I stop quilting before I do the last couple of rows. I trim the quilt to size, attach the facings, turn them back and pin them in place. Now I go back and do those last rows of quilting, holding down the facings in the "topstitching."
I still hem the facings down by hand, but that task is also a lot easier once the edges are firmly secured.
For a tutorial on how to sew on those facings in the first place, click here.