One of the first lessons I teach my dog is a strong hand-target. This is a basic lesson for many different techniques. I for example use hand target for teaching an «in» command or to teach rear-crosses.
This is how I want my hand target to look like. The toy in my other hand has high value, but Halli learned that he only gets it when he keeps his nose on my hand.
To learn the hand target I make it first easy for my puppy to touch my hand with putting food there.
I only treat from the hand the dog should touch, even though I later might hold the toy or treat in the other hand to try to make a «distraction». I also try not to put the hand toward the dog, he needs to find it.