Most of the people on this sight aren't good enough for making reputation. The only people I know are mods and people of higher classification. I give rep to people that have posted something funny, something of meaning, and things such as that. If something really makes me laugh out loud, I consider that a good reputation point adder. Or, if someone makes really good sprites and such, I consider that to be one, too. Only if the sprite makes me gape in awe though, which hasn't happened yet...
I give bad rep for people who double post, curse, or things of the same boat. If they have their sig too big (snicker, it rhymes!) then I PM them.
There...that's all I have to say of rep-giving.