Thanks Donny.
Put yourself in the right place in the right conditions as much as you can... the rest is fine tuning and comes with swing time.
One of the best tips I could give for beach detecting old items is... get to know how the different layers of sand and shell look, move, and react to different surf and tide conditions.
It reminds me of snook fishing in a way... once you get their feeding patterns figured out and can repeat the pattern your odds of being successful go way up.