Compliment sandwich

Instead of... "I hated the course content. Mr Smith was a great teacher but wasn't on time to class"

Say... "Mr Smith was a great teacher.  The course could have been improved by more industry relevant content and I feel I would have gotten more out of this course if Mr Smith had better time management. The last assessment was challenging but I feel as though it prepared me for my career"

Instead of... "Mrs Smith should be replaced because she doesn't reply to my emails. I liked the choices in the reading list but felt stressed about the assignments"

Say... "I enjoyed the selection of reading materials in this course. I could have further benefitted with improved communication from Mrs Smith and more guidance with the assignment expectations"