Personal letters. Writing letters. Letter to my friends

Letter Writing and Literature
One of the first prose collections to be called a novel, Samuel Richardson's "Pamela," from 1740, was actually in the format of personal letters, and that tome isn't the only fiction book that's taken that format in the centuries hence. The confluence of letters and books doesn't stop there, of course. In nonfiction, families compile old letters into books for future generations, and famous historical people have had their letters assembled into nonfiction works for posterity, either as a matter of record or for historical value. Take, for example, collections of love letters between presidents and their wives, such as the 1,000 letters saved between Abigail and John Adams.
"Some of the greatest writers have had their personal letters published as major works, often regarded as discussions of literature," notes author Donald M. Hassler in the book, "Encyclopedia of the Essay." "An early example would be the letters of John Keats, which were originally personal, but which now appear in collections of essays on literary theory. Thus the ancient form continues to have an intriguing ambiguity of purpose and a vigorous potentiality in relation to the essay form."
Letter Writing Today
But various electronic communication innovations over the past several decades, such as email and texting, have contributed to a decline in the practice of personal letter writing. It's more uncommon to see handwritten correspondence in the mailbox than common. Instead of having pen-pals, people communicate with others around the country and world through social media outlets. 
Even though blogging communicates in longer scripts than short-form tweets or quickie status updates, blog posts still are more impersonal than letters sent to a specific friend or relative; there's likely an expectation of more privacy, more "for your eyes only" when something comes concealed and wrapped up with just one person's name on it, more like a gift than a broadcast over the airwaves to the known world. 
"Today, personal letter writing is a declining art," writes Robert W. Bly in "Webster's New World Letter Writing Handbook." "Warm letters have always had a powerful ability to build goodwill. And in an age of computers and e-mail, the old-fashioned personal letter stands out even more. As we meet with our clients to brainstorm for their personal statements (or college essays), it reminds us how much we enjoy delving into the depths of our clients and helping them think about how best to tell their story. We are always amazed by their unique experiences and how they approach their lives differently depending on their interests or background.
However, it is also the most challenging part of the application process for most students. Up until now the bulk of their writing has been in the form of a non-fiction, analytical essay about a book they read or a history paper. Many struggle with what they should write about because they don’t know exactly what they want to communicate. And for those 17 year olds who know what they want to write about, very few know how to tell it in a compelling, interesting way. The personal statement must not only be compelling and interesting, but it should also convey the writer’s voice and personality in approximately 650 words.
I was reading a Forbes interview with Ryan Blair about how he became such a successful entrepreneur and it made me think how his story had all of the elements of a great personal statement. 
So what are some keys questions to ask yourself before you sit down to write to get at your own unique story?