We used Ship on producthunt for promoting when we were pre-launch. Then we had a decent number of subscribers built up so when we did a real producthunt launch

We used Ship on producthunt for promoting when we were pre-launch. Then we had a decent number of subscribers built up so when we did a real producthunt launch we already had people to tell about the launch. LinkedIn also worked surprisingly ok if you have a decent sized network. Finally, if your product fits a topic that's being discussed here on HN, we've seen that can easily drive 50+ your products landing page.