Michael asks, "I'm in the process of redesigning my website and creating a social media marketing campaign as a first step toward submitting a manuscript to an agent. It is my assumption that my website and web presence (YouTube, Facebook, Twitter, etc.) will be my most powerful medium for marketing my non-fiction, self-help book. Is this correct? I am also assuming that the larger the traffic and the larger my email list the more interest we will receive from agents and publishers. Are there any particular numbers I should reach before submitting to an agent?"
Thanks for your question, Michael. Your assumptions are on the right track. Agents and publishers are feverishly looking for authors who can bring a large platform to the table. A large platform usually means more guaranteed book sales and less risk for the publishers.
Thus, your amount of confirmed website traffic, social media followers, and newsletter subscribers gives definition to the reality of your author platform and ability to help sell books. As for exact numbers, that's a tough call to make. Every agent and publisher has different definitions of a "large platform."
I think a good number to shoot for is around 5,000 people on a newsletter list, monthly blog readers, and social media followers. Most non-fiction books need to sell 5,000 - 10,000 books for the publisher to break-even. So, if you can show that you help sell a large chunk of that amount, then you're more appealing to agents and publishers.
Social media is a great way to market books. However, don't forget the traditional face-to-face ways, such as public speaking and media interviews. A good marketing plan should feature a balanced approach of online and offline marketing tactics.
Frankly, I've yet to see social media show better marketing results than consistent public speaking and major radio/TV appearances. But, that will change with time.
Per your website, make sure it includes the key book marketing elements. I've got a free resource for authors at this link: www.startawildfire.com/authorwebsite.html