You can not find what you can not detect

A poor metal detector search coil sweeping technique is often the reason for an empty finds pouch. 

Beach hunters swinging metal detectors like golf clubs or scythes cutting grass, only really have a chance of detecting anything in the small area the search coil passes over on the bottom of the swing.

Beach hunters lifting or raising a search coil at the end of each sweep have target depth drop off substantially towards and at the end of each sweep.

Beach hunters walking at a normal walking pace along the beach, only detect a small part of the sand they are walking over.

Poor search coil sweeping technique, search coil control and metal detecting pace make more of difference in finds to a beach hunter than any metal detector being used.

You can not find what you can not detect!

Here are several things I do to maintain a clean sweeping technique and search coil control when metal detecting at the beach. 

I always keep my search coil as close to the sand as possible, including scuffing or scrubbing the sand ahead of me. 

I have a couple of youtube videos showing my search coil sweeping technique, check them out. 
To prevent me from traveling across the sand too quickly I always step (Not walk) forward and never step ahead until I have swept my search coil twice, slightly over lapping the previous sweep.

I only sweep slightly past shoulder width, a narrow sweep prevents me from over extending and raising the search coil towards the end of each sweep. 
These search coil sweeping techniques insure I never cover the ground ahead too quickly, miss easy to detect targets or lose any target depth. 
Help your metal detector to do it’s job of detecting the things you are searching for at the beach, the more targets you successfully detect the more success you will have.