Another route is to achieve celebrity first, and then sell the book. Certainly, if you want to sell a science fiction novel, it helps tremendously if you were in the cast of any popular genre TV show, like STAR TREK. If you want to sell a memoirs, the most important thing becomes to have had a memorable life.
Well, this guy has taken an interesting approach. His goal was not to sell a book, but he has in fact published one (also available on Amazon and the Kindle). What Matt Harding wanted to do most was to see the world, and now, at a young age, he's already seen more of it than most people ever do. And along the way, he discovered that if you dance badly, but sill dance, without regard for how silly you look, people will respond well. Thanks to YouTube and (eventually) Stride gum, he became an Internet and talk show sensation. Eventually, he put his journal into book form and now he's an author.
And all he had to do was travel on a shoestring, sleep in odd and often uncomfortable places, take some risks with his personal safety, and risk looking like an idiot. I could handle the last one, but the others are pretty much out. Anyway, I bought his book, and so far it's pretty interesting. The pictures do not translate that well on the Kindle (even the Kindle 2). They are black and white, but not always clear enough to see.
But I don't mind because I'd already watched the videos, and after I finish the book, I'm going to watch them again. Knowing what it took to get those shots should make them even more memorable.