Hi Bridget, there is a website that's called WrightsLaw that sends emails with general advice about advocacy. I apologize, I don't know about dyslexia. If you type it in their search box on the Wrightslaw site they have ten pages of responses. Here is a link to their page on how to write a great advocacy letter.
http://www.wrightslaw.com/advoc/articles/12rules_letters.htm

Youth lives by personality, age lives by calculation. -- Aristotle on a calendar