For this project I have been photographing many things arranged as shadow boxes. Part of the trouble is that the subject matter is recessed in the box and the walls tend to create a lot of shadow.
I placed the shadow box inside of a medium sized cardboard box wher I used a box knife to cut window like opens in the right and left side of the cardboard box and then another opening to shoot down inside/through the top of the box.
I then took large pieces of tracing paper and covered the window like openings. Then placed a hot light directioned through about 6-12 inches away from the cardbox on both sides.