What are the literary devices used in act 1 scene 3 of Hamlet? The part where Polonius is giving Laertes advice about his trip.

There are several literary devices used in this speech. First, we see a metaphor in Polonius' encouragement for Laertes to get going.

The wind sits in the shoulder of your sail,(60)
And you are stay'd for.

So he's telling him it's the proper time for him to be leaving. Next, parallelism defines much of the syntax in the speech. Parallelism is a structural balance of two or more words, phrases, or clauses. Some examples:

Give every man thy ear, but few thy voice;
Take each man's censure, but reserve thy judgment.

Give thy thoughts no tongue,
Nor any unproportion'd thought his act.
Be thou familiar, but by no means vulgar.

Finally, there are some examples of metonymy. Metonymy is the substitution of a word to describe something closely related to it. In his speech, Polonius tells Laertes, "Give every man thy ear, but few thy voice." So, listen to everyone, but be careful in whom you confide.