"Bringing it home" is making something more clear by seeing the situation more closely. Example: "Taking care of my grandfather is really bringing home the importance of good health care."

When one thing happens which shows you that some thing is real, that "brings it home". Example: "We knew the economy was bad. Bob losing his job really brought it home."

The thing that "brings it home" makes you understand the situation more clearly. Example: "I know this is a tough mathematical concept, but our next example should bring it home." Another example: "Who did their homework last night? Did that bring it home for you?"