Maybe not all of us, but some of us run into problems when trying to clamp up miters. They want to slip or move, and though they make miter clamps, they can still fall short when it comes to clamping them up.
I found this method and it really works soooo much better! When you miter the wood make sure to save the pieces you cut off, that way you can use them to clamp up the corners.
How is this done? This woodworker shows you. He even has a few bloopers on the end, so the video really isn’t but a few minutes. The individual also will show you how to strengthen the miter and hide a screw hole in the miter the right way.