In modern homes, it is unlikely to be possible due to space limitations, though traditionally, fireplaces were considered to be the right central element into a living room! But it's important to remember that the purpose of your living room is going to be inviting to people, to get them to feel comfortable and relaxed, and stimulate good conversation. So even without a central fireplace, making the fireplace some sort of center of attention will also work well. Mirrors are a wonderful tool to enhance Feng Shui in a living room. They bring light into darker areas and can reflect aspects of the area that visitors might not exactly otherwise enjoy. Mirrors make rooms look larger (and lighter) and very usefully, they will reflect the door, so any seating that cannot face the door can still have the door visible through the use of mirrors. Once again, we need to adapt this principle to modern cities and homes, even though the best placement for a mirror is when it can reflect a lovely view.