In honor of back-to-school, this quote is for all of the teachers who give writing assignments and who will spend the next nine to ten months begging their students in one way or the other to understand this very basic idea:
In some cases, the best design is no design, as with a love letter, which is simply an outpouring, or with a casual essay, which is a ramble. But in most cases, planning must be a deliberate prelude to writing. The first principle of composition, therefore, is to foresee or determine the shape of what is to come and pursue that shape.
– from Section II, “Elementary Principles of Composition,” in Strunk & White’s The Elements of Style, Fourth Edition