Making your audience want your product is one thing, convincing them to actually put their hands in their pockets is quite another. You have to get over their natural reluctance to buy or act. This can be done in a number of ways, the most common being the testimonial and the product comparison.
Testimonials are short quotes from celebrities or satisfied customers endorsing the product. Including one or more of these helps to reassure the reader that their decision to buy from you or use your service is a wise and sensible decision.
Comparing your product with a more expensive option also helps to encourage the conviction that the decision is correct.
Similarly, if you’re in a position to offer any sort of guarantee (“Your money back if not 100% satisfied) then this is the place to do it.