When we were doing Drop It, we introduced the concept by trading up - Oscar's got a stick or something, I say "Drop It" and pass him a squeaky ball. Once he had the basic concept we started applying it to low-value things with no trade-up. We didn't ask him to drop his rawhide, for example, just a small stick or a corn husk or whatever. As you go, work your way up to higher value things like chewies and favorite toys. We're still working on Oscar for his
really loved items but we try to remember not to just take things away permanently either. As in, I'll have him drop a stick, congratulate him when he does it, then pick it up and give it back to him. That way it doesn't become "every time I drop my toy/treat mom takes it away".
Oscar's an adult (adopted) but if he can handle it it should be no work at all for you to get your pup to get the hang of it
~Marrow