I had a successful "Show HN" a year and a half ago: 482 upvotes, lots of positive comments about my site. It even (tangentially) led to some business partnerships.

Here's what I think made it work:

* Above all, a good product that's worth talking about and learning from.

* A clear, unambiguous title. Don't piss people off with linkbait.

* Luck/timing. I posted it around noon Chicago time, which feels like a good time of day to post, considering major time zones represented by this community. And there wasn't any big tech news at the time, IIRC.

* Participation in the comments. One of the great things about Show HNs is the opportunity to ask questions and provide feedback to the poster(s). If you (as the poster) participate in discussion, it makes the whole experience better for everybody.

(Here's the Show HN link in question: https://news.ycombinator.com/item?id=4790636)