I have found that a very simple sheet of translucent vellum paper is a great styling aid. Vellum is commonly available in most art supply stores. Look in the fine art or scrap-booking sections. It can be a little expensive but if used carefully one sheet should last for many photos.
Here is a mousepad that I had made using a photo of some of my unfinished pendants.

The vellum softens the colors and my rue pendant is brought to the forefront.

I love to collect and buy artwork from other artists. As well as decorating my home they can be useful and beautiful styling props. I would suggest contacting the artist if you are planning on using their work. Asking permission is always appreciated and many artists will be very happy to have you use their work especially if you credit and link. Here is a beautiful mosaic piece from Margaret Almon of NutmegDesigns and the resulting styling.
I really love the bold patterns and naturally lovely colors of Tracy Melton's work at Focuslineart.
Even three dimensional objects can be turned into intriguing backdrops when you use vellum. Margaret Oomen's fabulous stones, found at RESURRECTION FERN take on a delicate mystery.
There are so many other possibilities that I want to try out - ferns/leaves, wood type, colored cords, marbles, starfish/shells. I think it also is a good way to create a unified feel using diverse materials.
Try it out and have fun!