Although not every tactic is used by every alienating parent, a common tactic is putting a child under pressure to choose between the target parent or the alienating parent, often by masquerading as the victim of the other parent’s “evil deeds” (which are often projection by the alienating parent). In order to side with “good over evil” the child must choose the alienating parent.
Another tactic is telling the child if they choose the other parent, they’ll never be able to see the alienating parent again. The alienating parent might emotionally blackmail the child saying they won’t love the child anymore if they aren’t the only one chosen. For a child, almost nothing is more terrifying then the idea of a parent not loving them. It puts the child in a kind of “Sophie’s Choice” bind, giving them a terrible power inappropriate to their age (or any age.)
Alienating parents can limit or even cut off the child from the other parent. The term “amputating parent” as been used to describe what the parent does overall but is particularly apt in this instance. This can be done a number of ways, either by the above tactic of making this the child’s choice, or by sabotaging visits with the other parent.