Somebody mentioned "reading the surf" recently. Lots of articles have been written about it over the years. Reading the surf usually applies to observing the breaker patterns for irregularities to locate a true gut (pass or cut or indentation on a bar), looking for busts, slicks, the usual concentrations of agitated baitfish, birds, etc.
Somebody recently mentioned shells, meaning living mollusks, clams and such, in the wet sand as an indicator for reading the surf for where to find fish. One of the most memorable banner days for trout for me on East G Beach in late June, early '70's green surf, SE wind, moderate break, featured an abundance of cylindrical, symmetrical (not like the conch), glossy, beautiful mostly brown-and-white colored shell units about 1 to 1.5 inches long, each one housing a living whelk (I think). They were practically piled in the first gut when the tide went out at the end of that day. (I don't recall if a depression out in the Gulf had the tides piled up or what.) I don't remember ever seeing them like that since. I've forgotten the common name--something like 'submarine' but that ain't it.
I found a pic of it on this poster, just to the upper right of the big conch in the center, but the print is too small for me to read.
There were big schools of good-sized surf trout piled up in there--no little ones. I caught 3-5 lb'ers on Mirrolures and spoons literally all day long that day, first from the near (2nd bar) and later on the far (3rd bar) as the tide fell. I've had some killer days in the surf in the 40 years since, and had days with two robust feeds early and midday, caught and released multiple trophy trout on top at high noon this decade, but I don't remember any day quite that good.
I don't hang out at the beach in late evening much any more, and only rarely see one or two of these shell units at the water's edge.
"It never was like it used to be." (Jack Saunders)
"These are the good old days." (C. Cimon)