1. Stay Leveled. The TV should be as close as possible to eye level when viewers are seated. Speakers should be at ear level.
2. How Far? Placing seating two times the distance relative to the screen size is a good general rule. Example: For a 42" TV, seating should be about 7 feet away.
3. Cut the Lights. You don't need to replace all of your drapery with heavy velvet, but a good rule of thiumb is to block out as much natural light as possible. Also, having dimmers on lighting is helpful.
4. Front and Center. Ideally, your TV should be straight on. As we all know, many floor plans don't agree. The best solution... choose a wall-mount bracket that lets you move and adjust the screen.