This is actually the hardest problem most startups face, the desperation spawned services like Product Hunt capitalizing on founders wanting success to be as simple as submitting a link to HN, Reddit, PH, etc.

The worst thing is practically everything you do in this space is going to fail, you can't solve it by adding features, nobody cares about your blog or self-promo posts, the only thing that really works is pouring money into advertising and that's a whole field of expertise too.