To get reviews from your customers you can use your existing email services. Send to ten or twenty of your customers and wait a few days to see how many respond to your request. See this page:
How To Request Reviews (reviewware.com)
You want to create a steady flow of feedback/reviews/testimonials from your customers, first for your own benefit, to know how your customers feel about your service. But, also because you can display their reviews to prospective customers. Just give prospects the link to your feedback.page.
Positive feedback from your existing customers will convince prospective customers to do business with you. Negative feedback will show you what you need to pay more attention to, making your business better.