David Krell’s article “From Book to . . . Blog? Inspiration for the Aspiring Nonfiction Author,” published in Publishing Perspectives is jam-packed with great advice for nonfiction writers. To sum it up succinctly: start garnering interest in your nonfiction book before you even publish it.
Krell offers five tips on how to build your author platform before you’ve even published books. He advises that you can score interviews and forewords for your book as well as lectures at conferences before you’ve even finished writing your book. This, in turn, will improve your chances of writing a well-informed book, obtaining a reputable agent, and selling your book successfully because you’ll have taken the time to build up your reputation as an authority on the subject and gotten other authorities on the subject to contribute to your book. You should read his tips on Publishing Perspectives for more insight on how to begin building your platform and become a successful author now, even before you’ve written a book.
In relation to Krell’s advice, here are a few questions I think a nonfiction writer should start thinking about as early as possible:
Who is your target audience?
What are the sub-themes of your book? What are the various angles you can use to market your book? (Krell’s book is about the Brooklyn Dodgers, but his friend suggests it’s also about urban history. One of my books is a memoir about growing up Greek American in New Jersey. It touches on family dynamics, coming-of-age stories, New Jersey, Greece, identity, and the immigrant experience. Another of the books I’m working on is about Jack Kerouac. Looking at it through a broader lens, it could appeal to anyone interested in the Beat Generation, the 1940s and 1950s, travelogues, and American history.)
Who would you like to interview? (Approach them now.)
Who would you like to write your foreword? (Approach them now.)
Who would you like to blurb your book? (A blurb is the endorsement on the back of a book. Approach people now.)
What associations are there for your subject? (Sign up for the mailing list, get to know its leaders, volunteer to help with an event or to write a guest blog entry.)
What conferences are held on your subject—or on your sub-theme? (Begin attending, meeting people, speaking.)
What websites are about your subject or sub-theme? (Sign up for their newsletter, leave comments on their posts, offer to guest blog.)
What books are similar to yours? (Read them to get ideas. Also, read the acknowledgements to find out who their agent is. Begin following the agent’s work to see if you’re interested in signing with them.)
Are there any other questions you would add to the list?
By thinking about these questions now, you’ll have a clearer vision of where you’re headed. You’ll also be more motivated to continue writing because you’ll have people who are already invested in your success.
Happy writing!
Stephanie Nikolopoulos 
Thanks Stephanie, a few more ideas for my book project in here.
Thanks for all the good tips