This happens with me too. My mind simply doesn't register what most people around me do or say as it classifies it as unimportant. I mean you couldn't care less if someone told you how their boyfriend never pays attention to them or what the girl next door is doing. I don't fucking care if your landlord extradited another 300$ from you. My thoughts are entirely centered upon myself and my actions, my beliefs and my behaviors and its really hard to communicate with people who I do not find interesting. People think I'm an asshole but I simply can't invest any energy in an interaction when I have to fill in the blanks and the person's not giving me anything to work with other than useless unimportant details.
So the best thing you should do is put yourself around people you want to be with so your mind will naturally want to pay attention to them.