There are several factors to consider when deciding where and how high you should hang a flat screen television. If possible, have a second person help you with this determination. In the room where you want to mount the flat screen TV, sit on the sofa, lie on the bed or get cozy in whatever position you would normally watch television. If the flat screen television is large and heavy, have the second person hold a picture frame or something similar up against the wall where you want to hang the flat screen TV. Many people tend to hang flat screen televisions rather high in order to balance the room aesthetically. However, if you hang the TV too high, it may be uncomfortable to sit with your neck bent in order to see properly, especially in a smaller room. If you find you are craning your neck or have a difficult time seeing that far, consider another height or wall.
Also, consider whether there will be any glare from opposite or nearby windows or even light fixtures. Take the time to experiment at several different times during the day and evening. Using a picture frame with glass will help you check for glare. If you have trouble finding just the right spot, you might want to rearrange the room and try again.