An email to a tutor about grades and feedback would start with a subject and the intent of the message expressed respectfully.
How to write the email
To write an email to a tutor about grades and feedback, title the email - Information about grades and feedback. Next, express your feelings on the subject. You may explain that you commend the efforts of the tutor in teaching the students but you believe that some adjustments have to be made in the way grades and feedback are conveyed.
Explain your proposal on the subject and express the fact that you will be happy if the adjustments are made.