- You can post it in places where people might be interested, like HN, Reddit, ProductHunt, Twitter, forums, etc. (carefully and thoughtfully, so it doesn't come across as spam).
- You can email it to people who might be interested (very carefully and thoughtfully, with an individually tailored message, so it doesn't come across as spam).
- You can email it to tech journalists, bloggers, and other people with influence, hoping that they'll help you publicize it.
- You can email it to a pre-existing audience you've built up if you're fortunate enough to have one.
- You can buy ads.
- You can produce content or do cross-promotion (which you say you don't want to do--it can work but certainly isn't required).
If none of the above is getting any traction, most likely the product and/or pitch isn't compelling enough and you should iterate on that before investing more time or money into marketing.
Anyway, my favorite book on the topic that I've read is "Disruption by Design" by Paul Paetz. One of the core ideas I took from it is about identifying the "Job to be done" that you're selling. As a marketing mentor once told me, nobody buys drills. They buy the hole.
Another important concept is knowing your audience (this was also the golden rule I took away from my degree program and has also served me well socially). Nothing is for everyone. Know that your audience actually needs the thing you're selling them. This also means that you can in good conscience be confident in selling it to them because you know they actually need it. Where marketing comes in is that they may not yet understand how your thing delivers the value they want and it's the job of your marketing/advertising to convince them that it does. Or they might see the value but think your price is too high. Then you have to decide whether you agree with them or explain why your price is fair for what you're delivering.
Anyway, as an engineer with a marketing education, I found it an enjoyable and inspiring read that was more direct and, I felt, insightful than other, fluffier marketing resources I've read. But it is more about the concepts and not about the gritty details (though for my money, observing marketing efforts at the companies I've worked for, doing your own legwork and meeting directly with your customers to understand their needs and pitch a trial of your product if it fits those needs is miles more effective than Facebook or Google ad campaigns - the only thing they have going for them is sheer scale at the expense of everything else).
Fair disclaimer, though: I have never run a business and never plan to. I just want to make cool stuff and my current employer is sufficiently fulfilling in that regard.
"A growth platform for hackers that hate selling."
It's a systematic approach to growth targeted at developers and based on the book Traction [0] by DuckDuckGo's founder.
0 - https://www.amazon.com/Traction-Startup-Achieve-Explosive-Cu...
But if you have above average engineering skills and make some technically engineered part of the business your secret sauce, that doesn’t save you from having to do the marketing but it does mean when other people enter you can compete on technical excellence with those above average skills.
That seems like a better plan? Maybe it’s a trap for engineers like me who want to keep focusing on the engineering, but it seems more viable than me marketing potatoes.