Hear everything Alfred has to say
Alfred is situated in the batcave. You can use X on him to listen to some dialogue from him from time to time. Whenever you get the chance after leaving buildings you enter as part of the story or a boss battle, return to the batcave using fast travel, look for Alfred (he has 3 or 4 spawn points) and speak to him. For some you may get xp for 'Alfred's Wisdom', these are the ones that you need.

There has been some discussion about whether this is missable or not. Some have claimed going back and forth from the batcave, speaking to him everytime and eventually getting the trophy (albeit some repeat dialogue) despite not talking to him much in the story. Others such as myself didn't have such luck, and had to do this in NG+. It is best to talk to him whenever you can as stated above, and if you don't get the trophy, speak to him a few times more after the story is over.