start off by taking three large shells that are about the same size and shape. make sure they are deep enough to hold some jewelery. you will also need an assortment of small shells for the centerpiece.
Next, you will need to glue the three big shells together. but first you have to put something in the middle. (it doesnt really matter what you use as it will be covered up later.)i used part of a plastic straw.
Finally, decorate the straw piece, or whatever you used, with the smaller shells for a nice, completed look.