When Polonius first enters, he chides his son, Laertes, for being late for his voyage and for making others wait for him. He proceeds then to give an extensive 25-line speech that, of course, causes Laertes to be even later. His speech is fatherly advice in the form of paradoxes:
Be thou familiar, but by no means vulgar . . .
Beware / of entrance to a quarrel; but being in,
Bear't that the opposed may beware of thee.
Give every man thy ear, but few thy voice . . .
He contines with others, including the advice to listen to the opinion of others but not give his own and to dress richly but not gaudily. Then he speaks perhaps his most famous line in the play:
This above all: to thine ownself be true.
Once Laertes exits, Polonius turns his attentions toward Ophelia, being quite nosey about her relationship with Hamlet. He then proceeds to bestow his bumbling advice upon her as well:
From this time / Be somewhat scanter of your maiden presence. / Set your entreatments at a higher rate / Than a command to parley.
Basically, his advice to her is to play hard to get--strange to hear coming from a father. He proves in this first scene that he is overly involved in his children's lives and is full of unsolicited advice.