When I signed a contract with Atria Books, I had a burning desire to make my debut novel a bestseller. I joined Facebook and Twitter, paid a designer to set up a sleek Web site, hired a freelance publicist, and filmed a trailer.

Then I learned others have done all those things—and still, heartbreakingly, watched their books flounder.

So I paid a tech-savvy college student to research top blogs in my genre and spent thousands in blog ads. I ordered postcards featuring my book's cover and plastered them on community bulletin boards. I spent my entire U.S. advance on marketing, and my publisher was doing its part to promote me, but I couldn't quash the nagging fear that it wasn't enough.

Hundreds of books come out every week, I kept hearing. Newspapers are folding, all but eliminating the odds of getting reviewed. People are buying fewer books. Even the biggest names in our business are scrambling for attention. Forget all the naysayers who tell you how hard it is to get a book published; the real challenge, it seems, is getting one noticed.

Then my smart friend Lindsay Maines suggested I create "Sarah Spike Day." If I drove orders a week before my debut, my Amazon ranking would soar, she said. A ripple effect would follow: Amazon would recommend my book more frequently, and booksellers would take notice. The Opposite of Me would get a running start.

My immediate reaction was to cringe: I'd be lucky if people bought my book; how could I be so presumptuous as to set the terms of how they purchased it?

Still, Sarah Spike Day had a nice ring. Maybe I could offer a raffle to folks who preordered, I reasoned. My publicist rounded up prizes, and Atria kicked in a handful of new releases.

That's when something extraordinary happened.

Jennifer Weiner, the New York Times bestselling author, heard about Spike Day through our mutual editor. It intrigued her. Jen was celebrating the 10th anniversary of her debut, Good in Bed. She wanted to mark the occasion by helping a new author. Though we'd never met, she'd read an early copy of my book and liked it.

Now, Jen is incredibly active on social media. Hardly a day goes by when she isn't interacting with her 60,000-plus fans on Facebook and Twitter. She isn't Oprah—yet—but her seal of approval is powerful.

I dropped my phone when our editor, Greer Hendricks, told me that Jen wanted to give away a personally inscribed book to every single person who preordered my novel.

Six days before my book hit stores, Sarah Spike Day launched. My friends spread the word, as did Atria's publicists. Jen was all over the place, writing about it on her blog, Twitter, and Facebook accounts. Soon, that shimmering, elusive phenomenon—"going viral"—occurred. Book bloggers chattered and tweets flew fast and furious. USA Today took note. It wasn't just Jen's big giveaway that captivated people; it was the subtle shift forming on the publishing landscape. Authors didn't have to wrestle over scraps of media attention; we could boost each other instead.

By midnight, my Amazon ranking had soared from about 280,000 to 62. The Opposite of Me broke the top 30 at BarnesandNoble.com. Jen happily bought boxes of her own books to inscribe, and my novel went into a second printing less than a week after it came out.

That could be the end of the story, but it was a beginning. Author Irene Zutell took the idea to Emily Giffin, who did a nearly identical promotion for Zutell's book. Then Jen Weiner created a raffle for advance copies of her latest book, Fly Away Home, entering those who bought the new Julie Buxbaum novel.

Other authors were watching. Allison Winn Scotch e-mailed a group including Jane Green, Jen Lancaster, and me, asking if we'd donate books to promote her new release. We all said yes—and Allison soon had 26 signed books to raffle off. The camaraderie sparked by Jen Weiner continues to gain strength.

As I kick off promotion for my second novel, I've learned that marketing my books requires every bit as much effort and creativity as writing them. But what I didn't realize is that I wouldn't be alone.

Washington Square Press will publish Sarah Pekkanen's next book, Skipping a Beat, next February.