This can clue you in to interesting facts about the person, like what they might want to hide and how they express their true feelings. 6. Take note of reactions. People's immediate reactions to different situations can be giveaways as to their true thoughts and feelings. Take a step back and let yourself focus on other people (you'll have a better time that way, too). 2  When you're talking to someone face to face and you're worried about whether your lipstick's on straight and how your laugh sounds, you aren't being observant.