I am in the same situation as you and while I don't have success yet (I just started three months ago), I have made many mistakes and have learned a lot. Here are a few tips:

- As an engineer, I got into a building frenzy in the beginning, and equated product building to building a successful venture. They turn out to be quite different in practice.

- Start getting interested users to sign up as soon as you can. Create a landing page, create a clear sincere description of the benefits (not just features), run it by as many people you can, and have a email signup so you can do that while you are building it. I have one at https://stockquanta.com and it has been quite successful in getting sign ups. I am still a month away from an MVP.

- Read up on marketing, validation and distribution. It's difficult to manage so many things on your own but it's still good to understand a lot of the essentials. I read this book and found it insightful: https://www.amazon.com/dp/B07FF51F8Y/ref=dp-kindle-redirect?...

- I initially thought that I will build first and then show it to everyone. That's a mistake. Try to talk to people early on about your idea and even better show them something working. You want to see how they react and if they truly get it. I have pivoted so many times based on how people respond. You want criticism and the honest truth.

- As a solo founder, the resources are limited. People have limited time. Something my GF mentioned that I have taken to heart is that try to maximize the user effort/user reward ratio. Think of Google...a few seconds of input gives amazing value. Can you shape your product such that you maximize this ratio? Can they benefit from your product within 30 seconds or 1 minute of landing on your page? This may not be possible for every thing, but it will force you to think of different ways your value prop can be presented. In my early experience, nothing sells better than a product that actually delivers true value in a short time frame.

- Have Plan B, Plan C, ... etc. Know that your initial proposed idea or execution might fail. Have an idea of how you will pivot next. You could pivot within the same conceptual domain, or have an entire new domain ready to work on. If you are relying on one thing only to succeed, that's a very brittle setup. The first product or service is mostly to optimize learning for the long haul. Learn everything you can about various things within and outside product. If you end up succeeding with the first attempt, that's an added bonus :)

- Read a few business books that relate to the lean startup, product validation, common mistakes early on. Learn from others' mistakes as much as you can so you reduce the likelihood of repeating them.

- Know that you will make many mistakes and there will be many dead ends. Don't compare your chaotic efforts with seemingly smooth success of others. It's never really that way. Make sure you are learning at every step, able to step back, look at the big picture and move on. Comparing your chaos to others' success can be very disheartening and unfair so be aware of that.

- Lastly, don't be that person who spends 2 years building and then emerging from a den. I know many folks who have done that and results are not pretty.