This is what I have done..sit on floor, hold enough treat so pup can smell it in hand, make a fist, let pup smell, pup will bite , nudge, push, etc..finally pup will hopefully sit an look at you and say "hey, what gives?"
quickly say "yes" and give treat with flat palm.
Pup learns to get treat, he sits and waits. You can also help control their movement toward your hand by holding collar as pup gets treat. Always push treat into thier mouth instead of allowing them to grab for it.
Add the word "nice" , once pup starts to figure out the game.
I've always taught an 'easy' command with my dogs using the fist method described above. Works great. (Now if I could get my cat to learn! She still gets me occasionally but doesn't actually pierce the skin. If I say 'ouch' she then lets them fall to the floor first and picks them up hehe).
Always treat with palms open flat...Are you practicing bite inhibition with your puppy?? If not, then begin asap...everytime u play or interact with the pup and it puts its mouth on you or ur clothes, give a short 'yip' or ouch and withdraw, the puppy should immediately stop, if it doesn't, then gt up and walk away for a few minutes and ignore the puppy. If the pup stops the moment u say ouch and/or licks u, say good boy and pet it...eventually it will begin to sense that humans are hurt easily and will gradually stop mouthing...this shud be practiced by everyone in your family (esp ur children if any, but always under supervision) from day one of getting the puppy as young ones learn quickly...with patience and positive reward puppies will learn to take toys or pick up treats without hurting you.
I put the dog in a sit, put a treat in my hand, make a closed fist. The dog will smell it, paw it, etc and I tell them to wait..as soon as they back off of the hand I open up my fist and tell them to take it, repeat as necessary, it only takes a few times and they get it. I have trained all three of my dogs this way with great results.