I would advise him who wishes to imitate well, to look closely into life and manners, and thereby to learn to express them with truth.
Poets are never allowed to be mediocre by the gods, by men or by publishers.
Luck cannot change birth.
He will often have to scratch his head, and bite his nails to the quick. [To succeed he will have to puzzle his brains and work hard.]
Tear thyself from delay.
Capture your reader, let him not depart, from dull beginnings that refuse to start