Newspapers, magazines, and radio and television stations, just like other businesses, value feedback from their readers, listeners, and viewers. Whereas letters from a national organization are sometimes perceived as an interest group “just doing its job,” letters from readers and listeners in the community can be much more effective.
Editors are not so concerned about perfect writing skills; they’re concerned about your opinions. Writing letters to the editor—and to businesses and lawmakers—is a great way of getting the message out.
PETA’s “Guide to Letter-Writing” brochure has more specific information.