Moreover, there is an unofficial rule of thumb which states that for every letter or call a politician receives, he expects that it represents several hundred votes. Get a list of your State and Federal Members. Find out which Minister or Member is most directly involved in the issue you are addressing. Make sure you get his name and title correctly spelled and make sure to get the correct address. It is surprising how often politicians receive letters they can't even read.
Politicians actually respond better to a hand-written letter.
But if your handwriting is atrocious, if possible, use a computer or typewriter. Write about one issue per letter. No more than one page if possible. Longer letters often are not read. Even if writing to a political enemy, write in a constructive, positive manner.