I found this on the "BringThemHomeNow" website.
Write letters to editors This is an extremely effective action, especially if there is an organized effort to get multiple letters placed. The letters section is the most read section of any newspaper, and politicians watch letters to the editor obsessively. Here's advice on writing 'letters to the editor' from FAIR (Fairness and Accuracy in Reporting):
Make one point (or at most two) in your letter or fax. State the point clearly, ideally in the first sentence.
Make your letter timely. If you are not addressing a specific article, editorial or letter that recently appeared in the paper you are writing to, then try to tie the issue you want to write about to a recent event.
Familiarize yourself with the coverage and editorial position of the paper to which you are writing. Refute or support specific statements, address relevant facts that are ignored, but do avoid blanket attacks on the media in general or the newspaper in particular.
Check the letter specifications of the newspaper to which you are writing. Length and format requirements vary from paper to paper. (Generally, roughly two short paragraphs are ideal.) You also must include your name, signature, address and phone number.
Look at the letters that appear in your paper. Is a certain type of letter usually printed?
Support your facts. If the topic you address is controversial, consider sending documentation along with your letter. But don't overload the editors with too much info.
Keep your letter brief. Type it whenever possible.
Find others to write letters when possible. This will show that other individuals in the community are concerned about the issue. If your letter doesn't get published, perhaps someone else's on the same topic will.
Keep the letter to 250 words or less.
http://www.bringthemhomenow.org/stand/speak.html