Is there a more powerful page on a website than the Testimonials one? Here are some ideas for yours:

Let your clients, colleagues do the selling for you!
 

If you wonder how to obtain testimonials:

• ask your current clients
• ask your past clients
• ask people you've collaborated with
• if you're just starting out, or changing the direction of your business, offer free service in exchange for a testimonial (and maybe a referral)
• look through emails and social media for any comments that highlight your service, brilliance, and results you've helped to create

And don't just focus on the work that you do - your potential clients also want to know what you are like as a person, how does it feel like to work with you... So, look for those, too!

P.S.: I just updated mine the other day! Check them out here and see how you can incorporate all those lovely emails and social media mentions...