Literary qualifications have no more to do with it than oratory has with salesmanship. One must be able to express himself briefly, clearly, and convincingly, just as a salesman must.
Ads are not written to entertain. When they do, those entertainment seekers rare little likely to be the people whom you want. This is one of the greatest advertising faults. Ad writers abandon their part. They forgot they are salesmen and try to be performers. Instead of sales, they seek applause