Ever just sat and watched people? Probably when you just didn't feel like saying/doing anything and happened to be in a social gathering wih friends. Ever taken a moment to sit and observe people?
You'd be amazed what you notice. Truly amazed and then you really discover more about the people you thought you knew. Or not. But try it. Sit and watch. You'd be truly amazed to notice those two with hidden feelings for each other or the shifty one or the one who just secretly eats everything hoping no one notices them or the attention seeker. You see them all when you sit back and look.