If your pup lunges: If your dog is going after something while on a walk — another dog, a car, a skateboarder, for example, be proactive. Try to redirect his attention with a treat before he has a chance to lunge, and increase the space between your dog and the target. Stay alert and be prepared before the target of his frustration gets too close. This type of behavior may be more common in herding breeds, but any dog can be startled by something he’s not used to or finds exciting.
Once your dog can stay in a sit for several seconds, you can begin adding distance. Place him in a sit and say “stay,” take one step back, then step back to the pup, give a treat, and your release word. Continue building in steps, keeping it easy enough that your dog can stay successful. Practice both facing him and walking away with your back turned (which is more realistic).