Some talking points for reference:
What was your experience working with me?
How did my work meet or exceed your expectations?
What specific challenges did I help you solve?
What aspects of my service stood out to you the most?
How would you describe the impact of my work on your business or project?
Would you recommend my services to others? If so, why?
How did you feel about our communication throughout the project?
Was there anything about working with me that made the process easier or more enjoyable?
What was your favorite part of working together?