For #nostr in particular, it means meaningfully engaging with people. The people on nostr noe don't care much about celebrity gossip. Teach people something. Inspire them to create something. Give them ideas.
I've had a #marketing person independently confirm what I deduced about getting the word out about what you do:
1. Think about your target audience and what they like. In this case, maybe disaster preparedness folks, outdoors people who have the courage and desire to wander outside of cell coverage, people concerned with surveillance and/or censorship, and so forth.
2. Figure out where they hang out and how you can reach them. Reply to forum posts where people are asking about off grid communications. Sponser podcasts that talk about these issues. Buy banner ads from bloggers.
And unless you're dumping tons of money into huge advertising companies, don't expect fast results. Organic growth takes time and effort. Like months or years.
On the flip side, it's not a lot of money, plus you get people who really appreciate the content and are less likely to get distracted by the next new thing that someone is advertising.