If there was only one thing I could advise you on, just one thing, it would be to check your holes again after digging a target.
Get into the habit of always ensuring there really is nothing left in the hole before covering it back up.
I went for a little beach hunt the other night and really was not finding anything (beach was sanded in) but then came across this one hole on the dry sand… the hole that kept on giving.
Started off with just a single tone, dug and found a 1 dollar coin. Bingo, before covering up, lets just check that there is nothing left in the hole, bang, another signal – another $1 coin! Check again, another $1 coin. Hole getting deeper now, repeat process and got 2 different signals, dug and found another $1 coin and a fifty cent coin. Checked again, another $1 coin. This hole kept me busy for a good few minutes which was great cause the rest of the beach was pretty dead. All in all, I got 10 coins out of this single hole, giving me a total of $9.50.
This is certainly the most amount of targets I have ever found in one hole (perhaps someone lost all their money out of their pocket and it fell all in the same spot or perhaps there is another bizarre explanation) but either way, always double check your holes. You will be surprised how many times you find more than one target in the same hole.