Testimonials are important in copywriting. Problem is, they're so overused and sugar-coated that they seem as if they're made up by a marketer.
Sure, testimonials are fantastic. But to readers, fantastic testimonials are fantasy.
Rather than grouping testimonials together in your copy and using flowery prose that sounds like a tween raving about last night's Justin Bieber concert, write story-based testimonials that help you overcome objections.
In other words, make your testimonials read more like case studies.
Include background or contextual information about the person giving the testimonial, perhaps prior to buying your product or service, and then use the testimonial as a way to let them explain what happened later while enjoying the benefits.
This is especially effective when your introduction includes some kind of objection that the reader might be experiencing. This way, the testimonial answers the objection rather than you and therefore appears less self-serving.