It's amazing what dogs are willing to do to please us. This is why they have been so useful, doing for us what we aren't able to do for ourselves.
So what were the steps to teach Luna to bring in the groceries? Here's a simplified list of the many skills that come together to perform this "simple" task.
1. Live bird, dead bird.
The goal is to encourage the puppy to release an object to you.
Wiggle the toy and play a little bit of tug.
Then stop wiggling the toy until the puppy gets bored and releases it to you. The reward for this is more wiggle and tug!
2. Play ball.
This is harder than it sounds with a puppy. They run, grab the ball, and run away with it. Their favorite game is keep-away, not retrieve. Don't play that game! When she comes back with the ball, let her keep it for 10-15 seconds. Either trade her for another toy, or pick her up. Usually she'll drop it.
So having treats in hand, we played in the hallway, where Luna had fewer options. When she came back, I immediately give her a treat. Eventually, (read, a long time) she understood to bring me the ball to get a treat.
3. Dog holds an object in their mouth.
Comfortably sitting on a chair, have the dog sit in front of you. Gently open their mouth and
put a dumbbell or something relatively uninteresting in their mouth. Immediately take it out
and reward with a treat. The goal is to have them reach for the object with their head. When
they'll do that, put it further and further from their head until you can put it on the floor and
the puppy will pick it up.
4. Come.
With the dog on a long (12-20') string or lightweight line call the dog. If they don't come,
gently reel the line in until they're in front of you. Reward. Continue until they reliably come
to you every single time you call them. Even when distracted.
5. Sit.
Hold a treat slightly above and behind their head. When they sit to reach for it, give it to them. Eventually combine that with the word "sit". Later on, (when you're ignored) you can
gently tuck their hindquarters under them to help them get the point. Never push down on
the hindquarters. You can injure your dog that way.
5. Front.
After the dog knows "come" ask them to come straight in front of you and sit. Once the concept is in place, you can cut a piece of foam insulation down to help the puppy understand
exactly where they're to sit in front of you. Only give the treat right in front of the center of your body.
6. Putting it all together.
As these 5 games become more polished, you can see how to put them together in little pieces until you can "play ball" and the dog understands to fetch something with their mouth. "Come" to bring it back to you. "Front" to sit politely in front of you and offer the object. "Dead bird" to allow you to take it out of their mouth. From then on, it's just a matter of
getting them used to picking up whatever object you'd like them to retriever for you. In my life this is most handy when I need my reading glasses!
Be patient. Rome wasn't built in a day. Luna is 2 years old and we play "train" every day.