What I do is harder to do in a low stakes game since there tends to be more players per hand, but give it a try...
Typically there are not a lot of players to the flop in a NL game. So when you are not in a hand watch the players in the hand. Watch each one as the action is on them for one round, watch them before their action on the turn, and after their action on the river. Sooner or later you have watched everyone before action, during action and after action. Don't forget to watch them after the showdown too, lots of information to be gathered there. Hear is a good read that has some good sections on information gathering/sharing...
http://www.tommyangelo.com/articles/reciprocality.htm
I also tend to "size up" players pretty quick, a skill that takes a leather ass to get good at. Players that I have a solid read on, I don't spend near as much effort/time in observing them. It's pretty rare that I get a big surprise anymore, little ones are common. Time in the seat...