How do you begin writing a complaint letter?

State only the facts—leave emotion out of it. You may be very upset, but whoever you're sending this letter of complaint to doesn't need that because it's going to overshadow the real issue. Instead, be very clear about what your dissatisfied with. For example, you might say "I dined at your restaurant yesterday. Typically, I have a wonderful experience. However, on this particular evening, I had trouble with my server Kate. She took a long time to bring us our food and bill, and she was very curt with us." If possible, put your specific complaint in bullet points.