"Interest" - All right! Your 'grabber' headline and magnificent photograph stopped the reader. Now, what else have you got that would interest your prospective customer to keep on reading the ad? A 'sub-head' , or 'bridge' piece of copy will do the job - if it's 'interesting'. Graphic design also plays a critical role in keeping the reader's attention. An excellent ad is built with powerful copy, excellent product photos, and brilliant graphic design.
"Desire" - Pass candy in front of a child's eyes and you'll see 'the look'. If your product advertisement is built correctly, you'll see the same look of desire in the prospective customer's eyes; the look of having been seduced. DESIRE is King!
The advertisement has to convince the prospective buyer that he, or she, cannot live without having your product. Or, if worded correctly, the buyer's already good life will blissfully be improved if they rush to purchase your 'luxury' product. If the prospect is desirous of your product, the prospect will sell him or her self.