For a 250-word review of Hamlet, you need to focus on the main plot line, analyzing how Hamlet ends up killing Claudius. Your introduction should cover the genre of the play and how it fits within the tradition of revenge tragedy. For characterization, you might want to focus on the indecisiveness of Hamlet and the "smiling" villainy of Claudius. For the plot, you should discuss the main narrative arc, including the appearance of the ghost, Hamlet's decision to feign insanity, the death of Polonius, and the play-within-a-play. The theme might be revenge. For a quote, the "To be or not to be" soliloquy is perhaps the best known passage in the play. Your analysis might address why Hamlet took so long to act, and your summary and conclusion recapitulate the main points of your essay.
For a 250-word review of The Tempest, your introduction should cover the back story of the role of Antonio and Alfonso in usurping Prospero's position as Duke of Milan. For characterization, you should focus on Prospero, Caliban, Ariel, and the two young lovers, briefly mentioning Alfonso and Antonio. For plot description, describe the arrival of Antonio and Alfonso on the island, the romance between Ferdinand and Miranda, and the happy ending. For theme, you could write about the issue of rightful rulership, addressing both Prospero's claim to Milan and Caliban's to the island. For a quote, use Ariel's song, "Full fathom five thy father lies ..." or Caliban's discussion of language. For analysis, focus on the question either of morality or of the relationship of magic to reality. The summary and conclusion restate your main points.