Use Bluestik putty to hold ornaments temporarily in place around the edge of the mirror. This helps you measure how many ornaments you will need and ensures they will fit before you start gluing. Meanwhile, heat up your glue stick.
Once you have all the ornaments in place, remove the putty and put glue where the putty was to permanently hold the ornament in place. Be sure to glue ornaments with the top side down for a more uniform look.
To embellish the corners, use a reflector ornament in each of the four corners. Put some glue on the back and place it on top of the corner cluster of ornaments.
Let all glue dry completely, then hang the mirror horizontally or vertically anywhere in your home.