We often need reminding even if we do not often need educating.
He left the name at which the world grew pale, To point a moral, or adorn a tale.
Learn that the present hour alone is man's.
Applause abates diligence.
You may abuse a tragedy, though you cannot write one. You may scold a carpenter who has made you a bad table, though you cannot make a table. It is not your trade to make tables.
If you want to be a writer, then write. Write every day!