Master the art of the swap: “No, you can’t have that—can you hold my purse/your doll/[this item] instead?”
When shopping, let your child pick one item that he can “buy,” saying, “You can pick one small toy to buy from this section—which do you want?” Or, “We can’t buy that toy, but we can get a book—let’s go over to the book section so you can choose one.”
Redirect his attention: “We can’t play with that right now—but I really want to play catch with you later. Will you go pick a ball to play with?”
Rather than simply taking the item away, involve your child by getting him to put the item away or give it back.
Tell your child that he can’t take the item home, but that when you get home you will make him a “present list” and make sure that item is on it. That way, everyone will know what to get him for his next birthday.