One of the assignments that I had to redo was making and attaching a cuff. The course taught only one way of sewing a shirt cuff. The placket was not what we are usually taught to make (you know, bound edges, a facing, or a shirt placket). Instead it was snipped at the ends and folded under. Whenever I made it following their instructions, it turned out wrong and frayed at the corners (as you can see in the lower photo). I knew that this would not pass so I found a way around it.
In the photo below you can see that I cut the fold about 1/4" longer on each side and sewed ever-so-slightly on the fold when I attached the cuff. Also, I made a horizontal buttonhole instead of a vertical one so the cuff stays in place better. It's a lot better like that and I got a Merit (I would have preferred Distinction, but never mind).
So that is how I made a cuff that doesn't fray. I hope that helps, especially if you are doing the same course (The Regent Academy's Fashion Design and Dressmaking Course 1). By the way, if you are doing it, please let me know if they have updated it. My file talks about the fashion of 1996 as though it's next year.
Until next time, Happy sewing.