three betting at the micro stakes

[HotPockets]

Okay, I wasn't sure if this should have gone in micro or maybe poker theory so I decided to post it here.

I'm a relatively new player toiling away at the micro stakes, and trying to grasp certain concepts. One thing I can't seem to grasp is the idea of 3 betting.

Aside from the monster hands, what are generally good situations to 3 bet light into? What cards do you look for to 3bet with? I will generally 3 bet any pocket pair from the blind if the button opens. Also, once in a while I'll 3 bet with suited connectors or one-gappers to isolate a raiser when i'm in position. Are either of these plays profitable at the micros? What about in general, or are they a leak I need to work on?