Ever try clamping at a diagonal from a corner of the workpiece? The clamp slides off, resulting in a few choice words. At least in my shop. So I found a quick and dirty way to clamp across corners.

A small scrap of wood with a V-shaped notch cut into it to conform with the angle at the corner. Attach to the corner of the workpiece with a piece of tape, and you're in business. The notch also distributes the clamping force over a larger area, avoiding the denting the clamp would otherwise cause on the corner of the workpiece.

Cut a V-shaped notch in a small block of wood. Soft wood is best as it will not mar the workpiece.	Apply a piece of tape over the v-notch to hold the block in place.
Set the block in place on the corner of the workpiece.	Glue, clamp, and voila!