This is the third time I have made this dress style and needed to make it a little bit different.
I like the look of flat piping opposed to corded on the edges of a dress but this posed a little problem for me as I couldn't butt the presser foot up against the cord to sew a straight line. First, I tried a normal foot but couldn't do it very straight and then used my blind hem foot (pictured below)
It butts up against the edge of the piping to give a perfectly straight stitching line.
Next I pinned the facing over this and turned the whole piece over.
Sorry for the bad photo, but I think you can just see the stitching line to the right of the foot; I used this as a guide and stitched slightly to the left to join the front, piping and facing together.
So when I turned everything to the right side my piping was perfectly level all round.
(my two rows of stitching on the armhole before turning)
Thanks for looking
pictures of the finished dress to follow!