I see a lot of poker strategy sites, forums, etc. saying that you should be observing your opponents at the poker table - and understandably so. But what sort of tendencies should I be specifically looking out for? Players who limp monsters, overbetting the pot when a flush rivers, 3-betting the button with mediocre hands like suited connectors, etc.?
And, with that said, how can I use that information to best benefit myself at the table and give myself a bigger edge?