4 ideas
The brewers said every brewery did the same, but no one had ever told the public, so Hopkins described the process in detail as if it were unique to Schlitz. Schlitz rose to tie for first place within months, because the first company to explain a common practice effectively owns it.
Every ad carries a coded coupon or offer, so returns can be traced to the exact headline, publication, and appeal that produced them. The cost per customer is then compared across variations, and small tests are run before spending at scale. Opinion and taste are replaced by counted replies, and any ad that fails to pay for itself is dropped.
An ad exists only to sell, so it should be judged exactly as a salesman would be judged: by the sales it produces measured against its cost. Fine writing, humor, and cleverness that a good salesman would not use in person hurt the ad, because they draw attention to the writer instead of to the buyer's gain. The copy should offer service and a reason to act, not boast or simply beg for the purchase.
Readers expect superlatives and vague boasts like "best in the world" in advertising, so they ignore them. An exact figure or a concrete detail reads like a verified fact rather than puffery, and it carries its full weight. A claim is therefore made believable by stating a precise number or process, not by stating it more loudly.