In the Know

How do you know someone? How do you know when this is accomplished? Is it simply a matter of knowing what they're like in certain environments and how they react to certain stimuli? Do you have to know minute details like a favourite colour/food/clothing/music/band/hair style/actor/movie/book/website in order to know someone? What can you tell someone to get them to know you better? What do they have to tell you to achieve the same thing?

ANd so on. Maybe I"ll work on this later.