My creative space is full of stuff in various stages of completion, so I thought I'd take the opportunity to demonstrate my way of doing an all in one facing, expertly demonstrated by Sherry recently. Her method works for pretty much all applications, mine only when there is a centre front or back opening in your garment, and wide enough shoulder straps. I find it easier, so I thought I'd show it here in case anyone else might benefit!
As mentioned, the garment must have an opening in CF or CB. Begin by sewing the shoulder seams of garment and facing and press them open. Since my facing is going to be on the outside I've sewn the dress with wrong sides together and facing with right sides together. This means the seams will all be enclosed when the dress is finished.
(Apologies in advance for the rather over-exposed photos in this post - my desk is bathed in sunshine during the twins' nap time!)
Then sew the facing to the garment around the neckline and armholes. If you're inserting a zip, leave about 3cm unsewn at the CB edge. I'm not so I sewed it right to the edge. Most importantly, leave about 3cm unsewn at the armhole edges.
Clip the curves so they'll turn evenly. I always offset my clips so that where the "Vs" form by opening out a curve they aren't in the same place on garment and facing seam allwances. This makes for a smoother edge.
Then turn the garment right side out by pulling the backs through the shoulders.
At this point I pin and edgestitch my neckline because it's easier when it's flat and the way my CB opening is finished won't be affected by it being done now.
Next sew the side seams of garment and facing, and press them open.
Then finish sewing the facing to the garment around the bit of armhole left unsewn, and finish clipping the curves.
After edgestitching the armholes, it looks like this.