Writing a letter to the editor

This past week we had to write a letter to the editor at the Washington Post about a story on the University of Maryland wanting to show a porno film. I found this to be real hard because I had no idea where to start. After seeing some of my peers letters in class it helped me some to see what maybe to write, but I thought that it was real difficult because before we had to write this I don't remember seeing any examples of letters to the editor.