From what I've observed on other sites (mostly StackOverflow and Reddit) I think there are a few major components to this, namely: timing of post, luck / random

From what I've observed on other sites (mostly StackOverflow and Reddit) I think there are a few major components to this, namely: timing of post, luck / randomness regarding early upvotes, and other posts during that day. The last one is a bit like when a film releases on the same weekend as some blockbuster, it is more likely to go under the radar. The middle condition is mostly luck, unless someone is prepared to manipulate the early upvotes somehow. But the first one is quite easy to time correctly - US-heavy sites tend to have a few time slots where a disproportionately large number of people check it. My guess would be morning, lunch and afternoon slots, and especially slots where different time zones overlap. E.g. an afternoon slot for Europe which overlaps with the Eastern seaboard doing a morning check of HN might work quite well, etc. This can help a fresh post break through the decaying, but highly upvoted older posts that are keeping it from more visibility.