Using a Tiny Paper Mache Box (bit.ly/1xCfHld) remove one side from the larger piece and draw a curve on the smaller piece as shown.
Cut along the curved line as shown, keeping the edges attached as shown.
Curve the edges to break up the fibers and glue them into an arched shape as shown. You can sand the edges to create a smoother shape.
Wrap a strip of paper, taller than your box, around the sides of the box.
Clip darts into the paper that meet the edge of the cardboard.
Fold the edges over and glue into place.
Trace and cut the shape of the stage onto thick card. Using a stylus type tool, score lines into the card to simulate wood planks. Paint with brown acrylic and apply darker washes to add depth.
Paint the larger piece black. Add a backdrop to your scene. This one is from this collage sheet bit.ly/1M5FwAg
Add layers of swags and curtains. Fold small wings on the sides to hold into place. You can also the bustles from the frocks in collage sheets in this kit to create curtains bit.ly/1E5wkYy
When you are satisfied with the look of your set, affix the top of the stage to the bottom floor.
Adding dresden borders to your stage will give it an ornate appearance and give you beautifully clean edges. You can find all sorts here: bit.ly/1OB48zQ
Tiny finishing touches and flourishes will complete your piece.
Add delicately cut teeny weeny players from the French Ballet Costumes Collage Sheet (bit.ly/1M5K6i7) and all the world's a stage.