You have to collaborate with influencers (YouTubers, Instagrammers) or complementary companies (luggage, travel pillows, etc.) with a bigger audience than you. If they recommend your site in their blog or video and vice versa, then that will grow your audience.

One way is to create a landing page with the option for people to include their email address if they want to be updated about the product/ service when it's available. Apps often do this while they're creating the product.

It depends. Video is very different from audio. What is clear visually on-screen might not be understandable to people listening to audio. If you listen to podcasts, the host and guests make sure to verbally paint a picture for listeners (what something looks like, what something felt like, smelled like, etc). It’s more about storytelling vs. just reacting to things without context.

A fast way is IG Live or FB video. People want to interact with you and ask questions in an informal way.

Focus on ways to share your expertise - public speaking, podcasts, online tutorials, workshops, coaching or selling/licensing your ideas to companies.