I recently picked up a copy of the works of the Roman poet Horace, and have been enjoying it thoroughly. It is translated into English, fortunately for me, though I suspect the translation does not do full justice to the beauty of the Latin verse. But the wisdom and especially the humor come through clearly over 2000 years later.
In his last years, circa 15 BC, Horace wrote a treatise of sorts, the Ars Poetica, the Art of Poetry, summarizing his approach to writing. Here are some of my favorite lines:
Mortal works must perish
It is not enough that poems be beautiful; let them be tender and affecting, and bear away the soul of the auditor whithersoever they please
This, or I am mistaken, will constitute the merit and beauty of arrangement, that the poet just now say what ought just now to be said
You, that write, either follow tradition, or invent such fables as are congruous to themselves
If you offer to the stage anything unattempted, and venture to form a new character; let it be preserved to the last such as it set out at the beginning, and be consistent with itself
To have good sense, is the first principle and fountain of writing well
Poets wish either to profit or to delight; or to deliver at once both the pleasures and the necessaries of life.
Whatever precepts you give, be concise; that docile minds may soon comprehend what is said, and faithfully retain it.
When there is a great majority of beauties in a poem, I will not be offended with a few blemishes
As is painting, so is poetry: some pieces will strike you more if you stand near, and some, if you are at a greater distance
You will have it in your power to blot out what you have not made public: a word once sent abroad can never return
In my judgment the Fauns, that are brought out of the woods, should not be too gamesome with their tender strains, as if they were educated in the city, and almost at the bar
And finally my favorite:
Those who are wise avoid a mad poet
