I just want to add that Karma's value doesn't affect your overall gameplay. I mean karma won't affect your stats gain or how much nerve you have, or how much money you make.
I tend to use it as a way to see how "helpful" someone "may" be (kind of a terrible metric but it semi-works) like, when you see a player profile, you can tend to find a more helpful player if that person has a large "friend" base vs enemies.
My main point is - don't feel like it's a stat you have to powerhouse toward and try to post everything you think of to get. It won't work well and when you end up in the forums it's more about the worthy read or a good helpful post.
You will meet a lot of salty people especially if you whore karmas at such young age and low battlestats. However, it really depends on how you see the game and your goal. If your goal is social aspect then by all means go farm karmas . If your goal is other thing, imo just be silent reader. Safer that way. And for the "how", kelsie explained perfectly
Karma isn't at all important. People can give your posts a thumbs up, or down, which gives you more (or less) karma, but it really has no effect on game play.
You can get a few points by asking how to get karma.
But generally speaking, karma's gotten through upvotes on your posts/comments. It's not required by any means and serves as an ego booster similar to Facebook's likes