If you're working in a school, may I suggest that you do like Arne Duncan says to do, and raise the bar. You might even want to change the game. Ask people to post their advocacy letters on a bulletin board; use a checkoff list. Give people little gold stars. Set a goal for x number of letters and faxes by a certain date.
Colleagues sometimes ask me what to write--- and sometimes I help them. The thing is to do a bit of research