There is a well known beach hunter named Gary Drayton who has published quite a few books about beach hunting ... Google his name which will take you to his website... He also has a blog he posts most weeks which gives you some good information about how to read a beach. Pretty sure he is a member of this site - look him up and send him a private message.
I think you also need to take into consideration what type of beach you intend to detect ... For example, our beaches in metro Adelaide are located in a gulf - which shields them from the "open ocean" and protects them from weather which would see other beaches like Sydney get ripped up pretty good... Also good to take note of drainage points which seem to take a battering after a good rain here - local knowledge is everything.
I have been doing a case study of two particular beaches over the last six months... Turning up at all times of the day and night and monitoring what happens after storms, summer, etc ... And can say that it helps me greatly in determining where to start looking and also where not to waste my time looking.... You see for yourself what types of activities are going on - where people are walking the most - and when one of those storms comes through you can easily identify what has changed. I know some beach hunters like to go to different places all the time, searching out new patches, but if you never return to a location often enough you won't know what has changed, where the recent activity was, and never really learn enough about a location to be successful on a regular basis... My two cents