Give thy thoughts no tongue, Nor any unproportion’d thought his act. Be thou familiar, but by no means vulgar. Those friends thou hast, and their adoption tried, grapple them unto thy soul with hoops of steel, but do not dull thy palm with entertainment of each new-hatched, unfledged comrade....
Act 2, scene 1
By indirections find directions out. So by my former lecture and advice shall you my son. You have me, have you not?
Observe his inclination in yourself
My lord, I have
Act 2, scene 1
Farewell.
The advice Polonius gives to his son is a massive list of nonsense. Keep your thoughts to yourself; do not act rashly; treat people with familiarity but not excessively so; hold on to old friends and be cautious about trusting new friends; avoid fighting but fight boldly if necessary; be a good listener; accept criticism but do not be judgmental; maintain a proper appearance; do not borrow or lend money and be true to yourself.
Polonius gives Reynaldo specific instructions for spying on Laerte's personal life.