Courts that use a landmark case as precedent for a decision are?

I believe the answer is: using an earlier case as a guide.

A case is considered as a 'landmark' case if it creates a huge debate on the effectiveness or  the eligibility of a certain law.
Such cases usually handled in the supreme court and the decision from the landmark case often used to handle similar cases in the future to prevent any prolonged discussion for the same topic.

True. Gestalt therapy is client centered psychotherapeutic approach that focuses on helping the client by emphasizing on the present to help the client understand what is happening around them. Gestalt therapy adopts a holistic approach in helping clients understand their relations to the world, and often uses role playing to help them adjust.