Seashells should fit the rest of your decor. They'll almost certainly clash with an industrial or high-tech theme, for instance, and will look out of place. Seashells look good with natural and more muted colors, such as earth tones, off-whites and pale blue, green and purple. These colors echo the natural theme invoked by the shells themselves. Bolder colors can work, too, however. A bright purple or green room could have seashell accents, as long as other elements don't clash with the shells -- industrial piping and harsh metallic surfaces are out, in other words.
Try using shells in functional ways, like as a soap dish, potpourri holder or bookends. Display collections of particularly striking shells on their own if you prefer. Devoting whole shelves to a collection of seashells gives them the attention they deserve. Curio cabinets also let you display your shells in style. For a novel solution, hang them in fruit baskets, or fill artistic glass bottles with tiny shells.
Seashells make beautiful centerpieces, too. Place one big shell in the center, and surround it with smaller shells, beach glass and corals. Set them right on the table or within a shallow container of sand. You could also line a mirror or picture frames with seashells, as well as jewelry boxes. Create a mosaic of shells glued onto a board or canvas, or make elegant candle holders with shells spiraling up the base. Consider mounting small shelves and creating distinct arrangements on each one, using seashells and other natural objects like driftwood, cloth flowers and dried plants.
To make your decor more interesting, don't limit yourself to the shells themselves. Choose other accents like fossils, dried plants, live plants, prints of seashells or paintings of ocean scenes, as "Better Homes and Gardens" shows. Nautical accents like a ship wheel also work well. Shells go well with a Victorian theme, too, as shell collections help to create an ornate look, and they were popular during Victorian times.