Don't try to put everything you can possibly think of in the letter. It is better for a variety of people to write different letters so that all the points get covered. If anglers write back, the correspondence can more easily be continued. Send the letter to every paper. This is especially important with daily papers.
News soon becomes old news.
Watch out for any pro-angling replies. The former is preferable as some papers do not print letters from out of the area. A quick phone call to the CAA can answer any points you are not sure of. It is important to appreciate that there are risks involved in using the media. Either by intention or through ignorance, reporters and editors may publicise your campaign in a detrimental manner.