The full directions for writing a good testimonial/recommendation are linked here.
The important thing is to keep it focused on what you got from working with me and not about me.
You might try these sentences starters as you brainstorm your review/recommendation/testimonial:
1) Cherri helped me . . . 2) Through her teaching I . . .3) The overall experience of her class was . . .4) The resources and materials created by her were . . .
Or maybe these questions will work better to get you started:
1) What were you struggling with before you worked with Cherri that she helped you with? How did she help? 2) Are there things about the structure or mood of the class that were particularly helpful?3) What is unique about working with Cherri?