Place a treat in your fist. Let the dog try in any way possible to get the treat out of your hand including pawing, licking, and nosing your hand
As soon as the dog stops trying to get the treat, mark the moment. Then, immediately open your fist, say “take it,” and offer the dog the treat. The point is to show that not paying attention to the treat is precisely what earns the treat.
After several tries, the dog should start pulling back from your fist or ignoring the treat. Now, wait for a second or two before saying “take it” and offering the treat.
Place the treat on your open palm. If the dog tries to get the treat, close your fist around it and wait for the dog to ignore it. Once the dog does ignore it, say “take it”, and offer the treat.