Tie a long piece of fishing line to the top of an object. String the fishing line up to the catwalk above the stage. Have a person sitting there to pull on the fishing line when the prop needs to stand up. On the end of the fishing line, tie it around the middle of a metal bar to make pulling up on the prop easier.
Affix a wooden plank to the back of the prop at a 45-degree angle to the floor to help support the prop. Nail the board to the prop using a hammer and 1/16 inch nails.
Mount the prop on a large sheet of plywood. You can use 1/16 inch nails to hammer the prop into the wood from the bottom of the plywood. Paint the plywood to the color of the stage to make it blend in.
Take off the top part of an old music stand so that you are left only with a metal rod and the three-pronged feet. Tie the prop to the stand using fishing line or insert the stand into the middle of the prop if possible to support the stage prop. This option is great in an emergency when you don't have time to create supports.