Beach detecting tips?

Beach detecting tips?

Its been ages since I went on the beach but I was down near the bay today giving someone a quote to build a pizza oven, so I wandered over the road and gave Sandringham beach a going over.

I was amazed at how the tides can roll up alifoil into perfect spheres, and lots of them.

Anyway, what to look out for? Tips needed.
High tide, low tide?

I did the spots where ppl would sit and got 2x 20c and 2x 5c coins, it was pouring down and blowing a gale so I only lasted 1 hour or so.