Consider the context of the dig. Many dig sites are not just barren desert, but places where people have accidentally come across fossils. For example, a paleontologist might get a call from a farmer who found some strange bones in one of his fields or near his barn. With this in mind, you could surround your dig site with cardboard cutouts of farm animals, farm equipment, and decorate the background scenery as if it were an expanse of farmland.
Add the tools of the trade to the dig site, such as pickaxes, hammers, brushes, scalpels, plastic bags for storing bones and other fragments and notebooks for keeping records.
Make the dig site realistic by creating an uneven digging area or hole, with a few bones or objects jutting out of the ground or in the process of being uncovered. You could even set up a small fence around the dig site made of wooden dowels and twine to mark off dig sites, if there are multiple ones in your scene.