An easy way to unify your home design is to have a common theme everywhere. When buying furniture and accessories, consider the materials of the items you are going to buy. If you don't have free walls and you have a fireplace centered, place floating seats in the center of the room. Place the chairs and sofa facing each other to encourage conversation.
Secure the furniture group with a rug and a large coffee table. Frame the space with additional seating and cabinets for storage, placed around the perimeter of the room. Placing furniture around a fireplace, especially in winter, makes your living room feel cozy and inviting. The way you think you're going to use the house and the way you actually live in it are usually two different things.