An Overview of Passages and Important Words

"loose and fishmonger"
Acting as the King's spy, Polonius demonstrates no respect towards his daughter in considering on "loosing" her to Hamlet. His words imply her to be a caged animal under her master's bidding and held without freedom of movement or will. To refer to using his daughter as loosing an animal, specially to spy on Hamlet, belittles and degrades Ophelia.
"To be or not to be"
Remembered and honored for its potency, this phrase deserves to be uttered with moderate pauses to emphasize Hamlet's fragmented and fractured state of mind. This rhetorical question that Hamlet repeatedly asks himself throughout his soliloquy demonstrates his confusion and emotional suffering brought on by the recent death of his father and his mother's marriage to his uncle Claudius, now crowned as King. His powerful, rhetoric words illustrate the intensity of his bewildered thoughts.
"St. Valentine's"
Her mind completely fractured, Ophelia wanders in her speech and mentions the thought of St. Valentine's as a joyous, romantic occasion for a young couple. Unfortunately, she believes she no longer has the opportunity to experience a romantic wonder with Hamlet. I imagine Ophelia uttering St. Valentine's with a tone of despair, hopelessness, and wanting.
"Give me some light"(Emphasis on "light")
Overwhelmed with the familiarity of the play's plot, the King momentarily succumbs to the guilt of his murder, his assumption of the crown and throne with bloody hands. As his guilt nearly overwhelms him, he demands the people to leave in order to regain his composure and hide any physical signs of his guilt. His words can be understood as figurative language, to ironically focus the audience's attention to the guilty King when he demands to be alone or the somber, dark conscience of the King.
"the play's the thing"
Confused by the recent knowledge he obtained about the murder of his father, Hamlet declares the play as the snare or light that will reveal and confirm whether or not Claudius murdered Hamlet's father for the throne. With the iambic pentameter having stressed(play's,thing) and unstressed(the,the) syllables, I imagine Hamlet speaking these words fluidly and wittily, with a touch of humor.