Diversify

As you can see by these photos, I try to make the most of the area I live in by going exploring and trying out of the way beaches.  

Just because you are a beach or shallow water hunter, does not mean you have to go to the same beaches all the time. 
During slow sanded in conditions is the best time to try remote out of the way beaches.
It is amazing some of the stuff you can find on remote beaches, you wonder how the those objects ended up in the middle of nowhere. 
If you do not have any mangroves or off shore islands to explore, try inland freshwater sites in search of old swimming holes.
Taking a chance and trying other forms of beach or shallow water hunting charges your treasure hunting batteries.
The risks are minimal if you venture out during sanded in conditions or if you are in the midst of a finds slump. 
The rewards are great if you are lucky enough to find a beach or swimming hole that has probably never seen a metal detector. 

Doing a little research on the area you live in should provide you with a few good treasure hunting leads to follow. 
I know of many people that got into beach and water hunting and found some really nice finds in areas that the average jewelry and coin hunter would never have thought to search. 
Sometimes beach and water hunters can be there own worst enemies by going to the same sites over and over again.
Try to explore and add new sites, no matter how many productive sites you already have. 
Beach and shallow water hunting is a bit like investing in the stock market, the more diverse portfolio you have, the more chance you have of making a profit. 
Remember why it is called treasure hunting, you have to hunt for the treasure!