If you want to capitalize on your Product Hunt launch, I've seen people have success blogging about their launch experience and then getting a second bump in traffic from sharing that post on Hacker News, Indie Hackers, and Reddit.

In the long term, though, you're in the same boat as everyone else: you have to find sustainable marketing channels that work for your business. I highly recommend Traction[0] by Gabriel Weinberg to learn more about growth and marketing.

[0] https://medium.com/@yegg/the-19-channels-you-can-use-to-get-...