Educate yourself in what people wore long ago and will wear in the future. Think beyond your closet. Language is big and is usually very telling of a person's background. Some people can't read, never mind recite poetry. Many avoid newspapers and books while others read everything from cereal boxes to classic literature.
People vary on many levels.
When writing give a solid view of your character's world. Show her avoiding certain areas or commenting on things she sees. Keep it real - alleys, rural areas and slums are part of any place, it just depends on how well they're hidden. I hope this article pulls you out of your everyday world so you can write another layer into the worlds and characters you imagine.