I was so frustrated with binding and mitered corners that I used to round off my corners and use bias binding since it's one pass and you're done...none of the fiddling at the corners. I thought I had read enough and tried many times to make it work, but miters never looked like they were supposed to.
There was one tiny thing that was never illustrated enough for me to "get it": When you get to a corner that you plan to miter, you stop stitching 1/4 inch before the end, secure the stitching and cut the threads to fold the binding to make the miter. Pin the folds or secure however is comfortable for you and put the piece back under the needle. Begin sewing at the beginning, NOT 1/4 INCH AWAY FROM THE BEGINNING. It sounds really silly for me to sit here and tell you how many times I started stitching 1/4 inch in and could not figure out why my supposed-to-be mitered corners were a big jumbly mess. One day I "forgot" and sewed from the beginning and nearly had a heart attack as I turned my binding over....It was perfect.
It's not really difficult once you work out your own system. And the effect it adds is worth a little extra work.
Good luck to you!