I created a shadow box several months ago, but have not tried a still life until this morning. I woke up with a real desire to get to the studio and get started. My wife put about 10 items in a box for me, and I through in a couple of bowels and some marbles. I put everything in the shadow box, turned on the light, and tried to subtract items in order to put together a reasonable composition. I didn't come up with a great one, and I believe I need some more interesting items with which to work; perhaps some colorful pieces of cloth, even a smaller box.
But, I did have a fun time trying a still life watercolor. Oils and perhaps acrylics, may be more appropriate, but again, I had fun and don't mind the outcome. Next time I will try oils, maybe.
Here is a photo of my box. I slipped a couple of watercolor boards inside to cut down on wall size. I maybe better cut the box down a bit. I also have the light coming in from the side and I believe many artists have a hole in the top of their box to get a bit different lighting look. By the way, that is supposed to be a little wooden box on a plate with two apples and three oranges.