The most important word in the vocabulary of advertising is TEST. If you pretest your product with consumers, and pretest your advertising, you will do well in the marketplace.
Source: In The Manager's Book of Quotations, by Lewis D. Eigen and Jonathan P. Siegel, 1989.
-- David Ogilvy, (Jun 23 1911-1999), US advertising executive; He founded Ogilvy & Mather advertising agency and created the Hathaway eyepatch man.