A little trick...

... with a facing and an invisible zipper. 
I am finally making a dress from a lovely African wax print that I couldn't resist buying earlier this year. When I was about to attach the facing, I realized this would be a great time to show you a little trick I had to find out for myself.
It's about how to get a neat point where the top of the zipper and the neckline meet.

It is possible that this technique is explained in lots of books on sewing technique. Books which I never bothered to read in their entirety. If you did, and all this is old hat to you, please ignore the rest of this post. 
I found out about this when I was still doing wedding dress alterations. At the first store where I worked, a lot of the dresses came with invisible zippers which sometimes broke (standard strapless wedding dresses usually contain too many layers of fabric and are pulled on too tight to make invisible zippers a good idea)  and then had to be replaced.
Whenever I took out one of those broken zippers, I noticed how neat and tidy those top points were. And so square! For all my careful zipper insertion, those points always came out a bit rounded because so much material was meeting there. 
Gradually, I came to understand that the secret was all about planning ahead and making the right folds and the right stitches at the right time. 

This is how it is done (works for facings and linings):

Press back the center back seam allowances before you even start pinning the facing to the neckline. On the outside, you already attached the zipper so that pressed line is already there. Press a little more back on the facing (assuming both pattern pieces were the same width). Pin the neckline an stitch, STOPPING at the pressed line on the facing.

Press the neckline seam allowances. Clip them where necessary and press them first open and then to the wrong side of the garment. 
At the edge of the zipper, on both outside and facing, fold the neckline seam allowance down first and then fold the center back seam allowance over it. 

This gives you edges without bits of seam allowance poking out along the center back. At this point, you could hand-stitch the facing to the zipper tape. I've done that for years. But you can do it by machine without messing up that nice corner.

Flip the whole thing inside out again and pin the pressed line on the facing to the zipper tape (make sure that fold arrangement at the top stays as it is).

At the other side, on the wrong side of the outside fabric, this should give you a little fold of excess fabric. That is what you want, it is the fabric which will cover the zipper teeth on the outside of the garment. Stitch where you pinned, stopping at the neckline stitching. It doesn't really matter whether or not you sew down the neckline seam allowance on the facing but leave the outside neckline seam allowance.

Turn right side out again. You make have to pull and push a bit to get all the layers back where they belong but when you have done that, this is the result!
I'm really glad I learned this trick and I hope it will be useful to some of you as well.