For mild guarding like freezing or staring, avoid reacting to not reinforce it.
Use treat tossing and praise to counter-condition positive associations.
Punishing guarding can make dogs more fearful and worsen the behavior.
Pick up items that trigger guarding until you've worked on training.
Hand feeding teaches dogs to associate humans with receiving food.
Trade a high-value treat when taking away guarded objects.
For moderate to severe guarding, seek help from a professional trainer