I also used a PTI stamp called Sand Swatch which I think is just right to look like the beach. This is the result, I think I'm really likin' it.
I used a couple of strips of a SU designer paper and tip top taupe ink along with PTI's Melon Mambo ink. I die cut the shell shapes first and temporarily stuck them to my Misti so that I could get the two-step stamping in the same spot. The Misti is the perfect tool for this.
The sentiment is from a older embossing folder from my stash. The "sand" die pieces were stamped onto kraft color cardstock and embossed with clear powder, I like how it makes the pieces really look like sand at the beach.
Anyhow here's the card...
Here's a close up of the embossing...
I made a couple more of the same card changing up the ink color on the shells to gold and adding a scallop frame, this is the result.