If you have a dog that is friendly with known people but wary of new people, this can also work. You will have to teach them how to play the game first and then you can use it when you want to introduce your dog to new people. The people may be new, but the game will be the same.
Before you start, you need to be sure the dog will eat in your presence; it won’t work if they won’t eat. Here’s how to do it: Sit on the floor or in a chair with a bag of yummy treats. The fearful dog will show you the distance at which they are comfortable being near you. Say it’s eight feet away; gently toss a treat past where they are comfortable. Try not to do a big overhand toss, which might scare them. They will get the treat and also get to move farther away from you – the perceived scary person. You’ll find dogs will tend to look at you after they eat the treat, so now is the time to toss the next one. Slowly they’ll start to think, “Hey, maybe they aren’t so bad after all. They aren’t trying to trick me into something.” After each toss, they may even start moving closer and closer to you… and that is the goal. If they don’t achieve that goal in one session, that’s okay; you can try again another time.
If your dog just needs some help with new people, teach your friends to play this game with you first. Start out the same with the unknown person probably right next to you. Still toss a treat away and tell them to “go find.” Once your dog gets the idea that “go find” means to go find a tossed treat, you can have strangers toss a treat and tell them to “go find.” Or you can have them on leash as close as they seem comfortable to the stranger, then you can toss the treat away from where the stranger is. Let them look back to the stranger and then toss the treat away.
You can also use this method to teach your dog about scary objects. When I first got Lillie, she always freaked out when we’d bring packages or grocery bags home. She’d approach and bark but be afraid of them. When she even just looked at them, I would toss a treat away. She’d look back and I’d toss another treat away. Like magic, she got closer and closer until now these things do not bother her at all.
There are several variations of this game, but the principle is that the dog is not being coaxed to approach someone of whom they are afraid. They are getting a treat reward and also getting the reward of getting to move away from the person or object they aren’t sure of.