Throughout the history of philosophy, thinkers have speculated about the nature of the ideal society. Their solutions say as much about the nature of the philosopher as they do about the nature of the society they seek to outline. Perhaps the two most famous attempts are set forth in Plato's Republic and Sir Thomas More's Utopia. Plato's account, like Sir Thomas More's about eighteen hundred years later, say a great deal about what each philosopher considers the formative influences on a given society.
In Plato's Republic, he discusses aspects of the ideal state on a very abstract level, beginning with the nature of individuals, the moving to the nature of the ideal society, and culminating in the government of that society. As an example, Plato emphasizes the place of justice and ethics in this society. They are building blocks for his society. Likewise, Plato discusses a number of other aspects of society (judgment, et al.) that an individual (and by extension society) must cultivate to approach the ideal. From there, he suggests that individuals with an understanding of the nature of justice will comprise the ideal society. At the head of this society is the "Philosopher King." The "Philosopher King" is one who holds complete power, not through intimidation but through the knowledge he possesses. In the "Allegory of the Cave," Plato illustrates how the "Philosopher King" differs from the rest of society. He alone seeks to leave the cave to approach a greater understanding of the world - to see the true nature of things (in the Realm of Ideas).
Rather than focusing on the nature of abstract concepts as the building blocks of a society from the level of the individual to that of society, Sir Thomas More's approach is a bit more direct. He concerns himself with the practical considerations. Like Plato, he does respond to political realities of his own time (Plato, not approving of Socrates's treatment at the hands of the democratic government in Athens, opts not to espouse a democratic government in the Republic.) Sir Thomas More, writing during the reign of Henry VIII in England, constructs his ideal state as a response to the nature of monarchical rule. More's state is essentially a socialist state, in which the population is given a certain task to fulfill. In exchange, the state provides for them. That being said, the leader of the state is not above the people, but he instead is responsive to the people. In doing so, the government is just (not being prone to excess of power).
These are just some of the many aspects each author discusses. While both propose a prospective solution to the question of an ideal state, More's, not only in its tone but also in its content, takes on a more practical form than Plato's. Plato is more concerned with the theoretical rather than practical application.