There is a shortcut to persuasive writing, and it's been around for 100 years.
It's like we got lost along the way, retreading the same old path of legal writing. Heretofore's and therefore's later, many lawyers still don't get it. Perhaps we are too proud to admit that we need editing.
We should take a page from Ernest Hemingway, one of the most influential writers of the past century. He was not a lawyer -- which may be one of the reasons he was a great writer -- but he was a master of concise and simple prose, which is the key.