Load up one of your favorite movies. You know - one that you've seen so often you don't have to watch it but will enjoy listening to while you work. If you have a small project, you only need a short movie. A twin needs a normal length movie, while a full or queen size needs an extended version. If you are attacking a king, load up a Star Wars trilogy. If you are
Put your project in your lap, back side up.
Take a little (2-3 inch) section of the binding and fold it so the binding edge meets the seam edge.
I usually thread my needle and put it through this fold from the wrong side of the fabric to the right side. This hides the tail of the thread.
Now fold that up again over the seam.
Insert your needle into the backing just above the binding. Be sure to catch only the back and not go through to the front of your piece. Slide your needle about 1/4 to 1/3 of an inch along the back and come up again through the backing, and the folded edge of the binding. If you made a good quarter inch seam, your binding and hand sewing will just cover that seam line.
Here's what it looks like when you come to the corner. You can see where the side you're working on is done and looks great, and the side you're coming to is open ready to be worked. Then there is that little funny spot in between that gets goofy. Don't worry about it!
Forget that cattywampus (a very specific and technical sewing term) corner for a minute and park your needle out of the way. Move two inches away from that corner and fold that section of the binding as previously instructed. Once that little piece is folded, continue folding backwards to the corner. You may have to attend to that last tiny bit, but it will then just come together.
See? Now retrieve your needle from it's previously parked position and continue sewing.
By the end of your movie you'll be all the way around, with smooth edges and beautiful corners that all look mitered.
YES, YES, YES!