A few years ago my mother-in-law remodeled her bathroom. I hit on the idea of adding seashells to a wall mirror. From there, I started making all kinds of gifts with shells. I prefer a 'natural' look to the shell placement, as opposed to the patterns found in commercially made shell items.
I have made dozens of these seashell-embellished frames to give as gifts, and have even sold some of them.
It's an easy craft to do. You can use frames, shadow boxes, mirrors, boxes, - whatever captures your fancy. Each one takes an little as 20 minutes, or as much as several hours to make, depending on the size and how elaborate you'd like to make it.
Step 1: Materials
Inexpensive frames and mirrors are fine. I find low-priced frames at places like Ross, Tuesday Morning, Home Goods, etc. I really like the chunky, all glass frames, as the shells really stand out and you don't have to use as many shells.
Plain wood frames also look good, but usually I cover these completely in shells, unless it's an otherwise dramatic or interesting frame.
You can purchase baskets or bags of shells at craft stores, or seaside gift shops. To buy a greater quantity, and spend less per shell, try online sources. I have had good luck with USshells.com.
The adhesive I prefer is Liquid Nails Clear Seal. It stays clear, and is gooey enough to keep the shells in place while I'm working on the piece, but wet enough to change things around if I need to. It may take a few days to be dry enough to package & give, so plan accordingly. I also like that when dry, there is still some flexibility to the shells in the piece. Sometimes a little give can keep it from breaking if someone hits it accidentally.