Love, love this technique! I used a white card for the base and sponged Distress Salty Ocean in "waves" making the curve go in one direction and then the other. It looked like a pool...
With another white cardstock, I partially die cut the flip flops from PTI's Flipping Out, creating the panel to be the "sand." Using the same curved line paper cut and a brown Distress ink to sponge the sandy waves, I sanded the area near the flip flops to appear as the foam on the shoreline. Stamping the flip flops separately, I added them with foam tape for dimension, with the straps and flower separately.
The water was sprayed with Shimmer Shine and the greeting embossed in white. The panel with sand was added with foam tape to rise above the water.
Love the way it came out and will use this set for tomorrow's challenge of one stamp set three ways!