Be clear about your reason for writing to Oprah. Her snail and e-mailboxes are filled with communications from around the world, and her staff has been trained to screen and discard quickly. Be respectful and mindful of the purpose of your letter and don't start drafting your letter until you are.
Limit your letter or e-mail transmission to Oprah to 500 words-- fewer if possible. A multi-page letter or e-mail is intimidating and off-putting, so make certain every word you use counts.
Begin your letter with an introduction that is so enticing, Oprah's mail screeners will be compelled to continue reading before passing it along to the next level (usually a producer who may pass it on to Oprah). Tell your story. Convey your emotions. Explain why you feel that only Oprah can help you.
Move on to salient points by structuring the letter with short paragraphs and bullet points. These writing techniques speed a reader through a letter, so use them. Don't waste time and words by flattering her. This could be seen as pandering.
Focus your letter to Oprah on one request only. Cluttering it up with multiple requests can be confusing and may move your message closer to the recycling bin than Oprah's in box.
Be direct. You'll waste words if you dance around points you're trying to make. "I'm writing because I believe you can help save my daughter's life by appealing to your audience for a bone marrow donor." A stand-alone sentence like this is the kind of statement that grabs attention and succinctly explains the reason you're writing
Don't stray into unnecessary detail, but do indicate the amount of effort you've already made so Oprah understands that you've undertaken due diligence. "I have already appealed to the Red Cross, Cancer Society, United Way ... "
Create a sense of urgency as you close your letter. Ask again if Oprah would be willing to air your appeal on her show, then throw in an alternative, "I understand that you may not be able to air my daughter's story, but perhaps you could recommend a service agency to help me as we're running out of time."
Maintain your sense of dignity. Ask for Oprah's help without begging or pleading, as difficult as this may be for you to do. It's important that you construct your letter or e-mail in such a way that you safeguard your future state of mind, regardless of the reply.
Add a P.S. to the letter. This old-fashioned addendum once graced love letters before turning into a direct marketing gimmick decades ago, but it's still as effective as ever. Using a P.S. increases the chance you'll get a response, so use this last opportunity to tack a succinct recap to your letter.