I like to approach these things with big wins.
One, ask yourself who your message would help? Who would find this really valuable? It may not be people you'd typically think. Look outside of your industry.
Find where those people hangout online. Where are they on Facebook? What are they reading? etc.
Then brainstorm ways that you can show up on those channels. For example: let's say your peeps love Forbes. Have you pitched Forbes yet?
Or let's say that mommy bloggers would go crazy for your idea (so you think). You hit up some of them via email and tell them you'd love to share this free content. You'd think it'd be valuable.
Content creators are always in the biz of finding more great content. So, when you can provide it and it makes sense (your job is to show why it makes sense) then people are happy to promote.
The scariest part about this is pitching it because it can feel vain.
The key is thinking about those you're helping, removing yourself from the equation and releasing the outcome.
Then see what happens :)
Happy to discuss in detail how you can find potential partners to promote your work, formulate the pitch and even create some email templates for you to send out on a call. Shoot me a message if you want to set up a call.