After you have your binding sewn on your entire quilt, you can see here it's all done, you stop about four or five inches away from where you started, and you cut your binding. You make them meet in the middle, and you measure. And the width of your binding, two and a half inches, is where you cut it. So you can see I've cut it two and a half inches. So once you've done that you're going to grab the two edges and put them on a diagonal together and pin them.
This is a little bit tricky, but it's really a good technique. I've tried many different ways to finish binding over the years and this is definitely the best way I've found. You're going to sew on the diagonal, from this corner to this pin. So you bring it to your sewing machine.
So after you've sewn from corner to corner . . . well, actually, after you've sewn your diagonal you really should mark it. It'll make your life a lot easier. You want to check and make sure you did it the right way, which we did. And then here's where I would just trim the seam allowance. You want to press it open, once again, so you have less bulk in the seams. We're just going to finger press it; fold it, and sew your seam. And if you've measured everything right it will just fit nicely.
And if you haven't you'll have a puff; but I think we are okay here. You have a nice smooth binding all around the edges of your quilt with nice mitered corners. And you should press them toward the back, and they're ready for the next step, which is to sew the binding to the back of the quilt.