Instructions
Move your router closer to your Xbox 360 if you are connected via a wireless network. The closer a wireless router is to the console, the faster your network can be. If you cannot move your router any closer, consider buying a wireless repeater, which acts a relay device for your wireless signal.
Move your Xbox 360 so it is not obstructed by any nearby objects. Do not have the console hidden in a drawer or next to walls in an entertainment system. You will want to limit the amount of walls and other objects that could potentially reduce the strength of your wireless network, if you are using one.
Update the firmware for your router. Manufacturers will often release updates in the form of firmware for their products. These updates typically increase the speed and overall efficiency of the router, which can significantly increase the speed of your upstream bandwidth.