Instructions
Check your TV's specifications to ensure it has an HDMI port.
Plug one end of the HDMI cable into your Xbox 360 Elite's HDMI port located at the rear of the console.
Plug the other end of the cable into the HDMI port on your television.
Power on the Xbox 360 and TV. Change your TV's input to the same HDMI input your console is plugged into.
Access the dashboard on your Xbox 360 and go to "System Settings."
Go to "Display."
Go to the high-definition TV setup option from the resulting "Display" menu, then choose the highest resolution setting possible for your television.