Writing advertising copy begins, as you might expect, with defining objectives - of the campaign, of the marketing program, of the specific ad and letting the creative juices flow...
Writing The Copy, Using Our Old Friend - The Alphabet
The artistry of advertising lies in the ability to manipulate symbols and ideas in order to inform and persuade people. As in any art form, there are no rules that can guide you in doing this, except to list those factors that seem to work most consistently. And yet, remember, some of the most successful ads are those that violate the rules.
Two universally accepted axioms are that an ad must be simple, and it must look and sound as if it's worth paying attention to. And obviously, it must be complete. it must contain all the information you want to convey. These axioms -- if indeed they are axioms -- spring from the fact that few ads are successful when these rules are ignored. Beyond that, clarity is essential. No matter how an ad is written it must be understood and easy to read.