Begin to gather and ask for testimonials.
Start noticing any feedback you get, and keep it in a Google doc or folder. You can cut/paste positive comments from social media or take a screen shot if someone gives you positive feedback, and share it later. If needed, you may scratch out the name to protect the identity of the person, or ask for permission to share.. Begin to collect this now.
Ask for testimonials.
Send a "feedback letter" after you provide a service, as a thank you, and include a survey for feedback. As part of the survey, include 2 or 3 questions for a testimonial.
The purpose of this course, if to help you get ready to do business. Take a moment and draft a letter than can be used for clients, and save it as a template on google docs. Or, use Survey Monkey, and create a few questions that you may like to use with clients.
Overall, just be aware when you receive compliments, and add it to your testimonials folder.
Do you have any testimonials you can use right now? If it applies for your business, make a list of who you may contact to gather a few, if you do not have any.