Over the past week or two I have really committed to making notes about what people play with when I sit at a table and their style of play. As a result I have found myself making calls I might not normally do after glancing at my notes about people at the table and what they have played with formerly. It has certainly paid off more often than not recently. Yesterday I made $20 (at .10NL) off of one guy because I called all-ins twice with J's and Q's, overcards on the board and he had a low PP and J9s - because I knew he normally raised, called and bet with crap hands hoping to catch river cards.
I would imagine most of the successful people here take notes while they play even if it's on the computer?