hey Jason don't be so hard on yourself , your best chances for old coins is researching where they could be . you have to find places that give you the best chances to find them , after all a park or school they built ten or fifteen years ago isn't really going to produce 50 or 100 year old coins unless they brought in fill-dirt from somewhere else that did. once you find a place your next biggest impact to help your chances is to know your machine well run it at it most maxed out settings ( i have not used the minelabs to help with this part , hopefully someone with experience can help) but still keeping it stable to understand , going slow , being patient . a good recommendation is to join a local detecting club , its a good place to find a hunting buddy and there plenty of experience to talk to .hope some of this helps .
Dan