I find it comical that the number is 500. It used to be much lower (Google searches show that).
HN keeps raising the bar in order to limit the # of people who can downvote. I would be genuinely interested to know what % of users that actually is.
The only way to get a large number of upvotes is to be lucky enough to post something at just the right time, or to make a comment on a controversial topic that most of the HN audience will agree with. Be careful, though, that you make the right political statement, though, because otherwise you will get downvoted and lose karma.
The story for most of us, though, is that we're just a second-class citizen here at HN.