Not a lot of people agree with me but here it goes:
Testimonials are not necessarily written as real testimonials. I have written many of them. If you are looking for genuine testimonials, yes you should approach people you have worked with, see it as a reference. But the average Jane Doe doesn't really care about names of leading people in the business.
Same as blogs, these are all written by editors, and the goal is to put in as much SEO words as your creativity can handle. So testimonials and blogs do the same thing: rank you higher on the search lists.
So you need testimonials? Write them!
I made half an annual salary writing comments on Amazon.com about products and how great they were. I made about a dollar a posting. Good money but totally made up I never used the product let alone I bought it. Amazon is only interested in high ratings, and that is it. People want to be deceived and the internet is the perfect platform to do that. Surf along!