This glass float piece is coming together in an odd way for me. I have the foreground elements done as component pieces. The sandy background has had me a bit stymied. I worked on it a bit yesterday, but was not happy with what I was getting. I woke up this morning with a couple of ideas—both less realistic, more stylized. Yesterday I was looking at photos of sandy beach and getting far too caught up in the way things really are! So I did a little playing in Illustrator and Photoshop this morning and came up with two scenarios, using a digital background and my photo of the float. You will have to imagine the foam added.
And jandj—your suggestion of making a sand texture by doing a rubbing from coarse sandpaper is exactly what I plan to do! I have done this before and it works great.