First off, I want to just note something.These are not points, getting Rep won't do anything for you, but let others know that you're a good member.
Although gaining Reputation Points, or " Rep " is as simple as clicking a down arrow or up arrow.Don't abuse this
The main point is, if someone was helpful to you, or you see a review that's just completely amazing looking " Wow, I would have never though of that.. That sounds awesome!! " kind of thing, give it the up click, and the person you up click, gets more positive, " Rep ".
Giving out negative rep is mainly for trolls, and people like that. Or people who just plain gave bad advise, etc.
So yeah, try not to abuse it. It would be nice to have a good system of Reputation around here.