If you have a large collection of shells, organizing them into glass jars will create a wonderful display. Gather a variety of glass jars in different sizes and shapes. You can find a wide selection at thrift stores or garage sales. The jars do not have to have lids, although that will help keep dust off your shells. Sort your seashells by type into separate jars. Label the jar by the type of shell inside, writing with a puffy paint pen on the glass. You can also tie a neatly printed label attached to a ribbon around the jar or glue a label to the lid.
If you have many smaller shells, you can use them to decorate a picture frame or keepsake box. A shell-decorated picture frame would be a wonderful way to show off a treasured photo from a family trip to the beach. Simply glue shells to an unfinished wooden picture frame, arranging the shells so they are just touching each other and covering the entire front of the frame. You can decorate a plain wooden box from the craft store in the same manner. Glue shells in pleasing patterns to cover the surface of the box. Use it as a jewelry box or to store other mementos from a vacation.
A shadow box is a wooden frame that has a glass front and a solid back, with a designated space between them. The front either lifts off or is attached with hinges so you can open the box to fill it. Display your shell collection by arranging the shells inside a shadow box. You can fill the box so that the shells cover the inside completely, or choose just your favorite shells and glue them into place, leaving space in between.
Use your seashells to create a centerpiece for your table. Start with a large clear glass vase or bowl. Arrange a layer of seashells on the bottom, choosing your best looking shells and larger specimens. Mix in a few ocean-worn rocks for interest. Once the bottom of the bowl or vase is covered with shells and rocks, fill the container with water up to the halfway point. Float a few candles on the top of the water for a romantic touch, and set it in the center of the table at your next dinner party.