Thank you for posting your question to the Ask Me Help Desk.
Below is a link that will take you to a page full of templates for various Microsoft Office products like Word.
Even if you do not have MS Office you can still look at the templates without downloading them and see how the various letters are set up to help you with conventions, organization, and presentation. You can also get some ideas of some various things to say as well which can help you with fluency and word choice. Voice, of course, you will have to come up with on your own.
Let us know if we can do anything else.
Office Templates