How to bind a corset neatly
Unfold one of the folded edges of the binding so that it is flat, fold over the spare inch at the end, align the raw edges of the binding and corset right sides together and pin into place. When you get to the other end, fold over the spare inch again and pin in place. Make sure that each edge of binding is also aligned with the edge of the corset.
You may find it handy to use the zipper foot for this because of the bones
There are a couple of options for finishing at this stage. You can either hand sew the binding in place (my preferred method), or you can "stitch in the ditch" for a totally machined look.
Then from the right side of the corset, stitch the binding in place along the seam which you had sewn previously - the ditch. This will ensure a neat finish on the right side - you should not be able to see the stitches....