Many thinkers, including, Freud, Heidegger, Wittgenstein, Pound and Koestler, have noted the German verb dichten—"to write"—also means "to condense."
The word stems from the Latin dictare, "to dictate." Ancient Roman poets used to dictate their verses to slaves, who wrote them down (hence, "condensed" them) on wax tablets.
The most persuasive writing is condensed.
Its strength comes from conciseness, what Hemingway called "leaving out*"—omitting everything that's irrelevant or obvious.
When you edit your writing, think of Darwin.
When only the fittest survive, what's left is stronger and better.
"Like passengers in a lifeboat, all the words in a concise text must pull their own weight," says journalist Danny Heitman.
Your goal in writing shouldn't be to inform, but to suggest—to help readers reach understandings of their own.
And your goal should be speed—speed that comes only from condensing.
"Modern prose had to accelerate its pace, not because trains run faster than mailcoaches, but because the trains of thought run faster than a century ago," Koestler said.
Here's an example of persuasive writing (85 words) from a white paper:
The resounding message surrounding Millennials is clear: Money means less, culture means more. But that’s not to say money doesn’t matter at all. As the generation with the highest rates of unemployment, lowest earnings and record student loan debt, Millennials certainly care about their financial health. A recent study from Gallup found that 48 percent of Millennials find overall compensation “extremely important” when seeking new job opportunities, and one in two would consider taking a new job for a raise of 20 percent or less.
Here's the same paragraph souped up (condensed by 35%):
Millennials are loud and clear: Money means less; culture, more. But it's not that money means nothing: Millennials suffer high unemployment, low earnings and crippling student loan debt. In fact, 48 percent say compensation is “extremely important,” and 50 percent would change jobs for a raise of 20 percent or less, as Gallup recently found.