Now, draw a line from the folded edge of the binding, in line with the seam, to the second mark you made and back to the seam. It should look like a right angle triangle.
Now you need to turn the corner right side out. I take my small applique scissors, but anything with a blunt point will work, like a pencil or a stick. Place it in the point of the corner and push it through, turning the fabric right side out. Use your turning object to ensure all the fabric is flat and the corner is as sharp as you can make it.
Pin the corner down and sew down as you've done the rest of the binding. I put a few extra stitches right in the corner.
6. Last stitch. For the last stitch - and every time you finish a length of thread - this is what to do. It hides your knot yet is quite secure.
Start your stitch as normal. Before you pull it through wrap the thread around the tip three times.
Pull the needle through, holding the thread against the binding fold. The knot should end up snug against the fold. Clip the thread right next to the knot and it will end up being virtually invisible.
And you're done! Personally, I find putting to the binding quite satisfying. The quilt will still need a label, but it is effectively finished at this point. Beyond the relief of finishing a project, it is about realizing the vision I've had and the excitement of passing it on or snuggling under it that night.