As a Service Providers,

Pay more attention on getting testimonials than getting money

The truth is that the more testimonials you have (about your service)

The more money you'll make

And how do you get fresh testimonials for your business (if you've never had one before)

It's easy,

Offer to work for free first in exchange for a testimonial 

Once the client agrees and you eventually deliver the job to them,

Request for your testimonial (as a means of payment for the service done)

And they'll gladly give it to you (if they loved the work you did)

That's basically how to go about it.