Stack Exchange is a weird place. I've generally found their user community pretty hostile. I find the idea of giving people badges for downvoting to capture something about their negativity.
The whole site is about gamification of altruistic behavior. Answering questions is important, but pruning the unhelpful answers is too.
Even when making an honest effort to engage in meaningful discussion you might get sent to oblivion without a single reply or any sort of guidance. It feels like I’m violating unspoken community rules and no one bothers to clue you in.
Example, I made a comment earlier pointing out that North Korea tends to reject outside help due to the juche methodology. That comment was at 3 points, now it sits at 0 and I really have no clue why.
At this point I don’t think I’ll see an upward trend in karma growth, not that it particularly matters.
On SO what you need to do is quite clear, on HN it’s (to me at least) a mystery
Just accept that silent passive-aggressive censorship is part of the culture here and ignore it.
Anyway, the secret to karma on HN is to submit interesting articles, ideally from sources that few people here are likely otherwise stumble across. While there are probably a few high scorers who get most of their points from comments, I'd bet the vast majority are from submissions.
And as the other reply to you says, don't pay too much attention to the points. Submit interesting stuff, keep making good comments, and please stick around.