John, unless you have pitched your idea to dozens of publishers and been rejected by every single one of them, I would keep trying before you take the self-publishing route. Why? Because if you self-publish you will still need to work like crazy to market and sell your book, which means you will need an even stronger social media presence (almost everything is sold this way nowadays,) speaking engagements, huge network, etcetera. You might as well make that effort with a book published by a recognized brand, which gives you more credibility as an author. This is what I would do:
- Study this book: Thinking Like Your Editor, by Susan Rabiner and Alfred Fortunato. They provide an excellent guide to writing a book proposal, which also emphasizes the social media/network aspect and why it’s important.
- Continue submitting your book to other publishers with a book proposal modeled after the book above.
- Work on growing your social media presence and your personal network. It’s not all about FB followers, although that’s important. You can give speeches or classes about the topic of your book, even if it’s for free, so you augment your network of contacts, email list or social media buddies. You can write more consistently on your blog about such topic, for ditto. You can become member of other people’s FB groups and be an active participant, so your name starts to ring bells, etc. I know. It’s a pain. I’m not good at that myself, to be honest. But I know full well that is part of being a writer nowadays, unless you’re lucky enough to have become famous before self-marketing was part of the writing business.
- Only if point number two doesn’t work after having exhausted all possibilities, I would self-publish, and be ready to do all of the above to sell your book like hot pancakes. Why? Because unless your self-published book is a smashing success, you will look even worse to the next publisher for your next book idea.
All that said, I think that rejection letter was awesome. For one, it tells you straight up that you have a great idea and an engaging voice. That’s gold. And two, it gives you the next steps you need to focus on to have your next pitch accepted. I firmly believe that there is a publisher out there that will take your book, if only you show a willingness to help with the marketing. The book I recommended above will give you some ideas.
Very good luck. You will get there.