I had a teacher that had a different idea with corners. Since we all don't use a 1/4 inch seam she taught us this way. It seems to work for me.
1. When you get about 2 inches from edge stop and fold a 90 degree angle with the binding. Make sure the angle is 90 degrees and either iron or finger press a crease on the angle folded edge.
2. Lay the binding straight and stop exactly where you needle reaches the crease.
3. Back stitch a few inches. Cut your threads and move the quilt away and fold the binding at the 90 degrees and then down, making sure the turned corner is exactly at top of quilt
4. start sewing again at the top edge the distance you are using.
Works every time for me. Hope this helps