Patience and instincts.

I have written extensively in my beach and shallow water hunting books about ways to increase your finds by timing your beach and shallow water hunts correctly.
One of the keys to being successful is learning to be patient, another is relying on your treasure hunting instincts if you are part time beach and shallow water hunter.
Knowing when to hit the beach during times of high surf, or knowing when to hit the water afterwards can really make a difference.  
Just like it is not a good idea for a weekend warrior to detect early on a Saturday morning before people on the beach have had a chance to lose anything, you have to wait for erosion to take place. 
Many beach hunters rush to the beach straight away when high surf is forecast, a good treasure hunting move, but only if you really know your local beaches. 
If you know how the surf height or direction effects your local beaches you have a big advantage and you can time your hunt much better.
This is another reason why it is so important to base your treasure hunts on your own instincts, instead of following the flock.  
Beach and water reading skills and being proficient at using a good metal detector can help a part timer treasure hunter to be just as successful as a full time beach hunter on eroded beaches.
So can patience and waiting until conditions on the local beaches are primed for treasure hunting.  
As I have also written in my books, sometimes it is just as important to know when NOT to metal detect on the beach as it is to know when to metal detect on the beach.