Remove the logic board assembly from the MacBook Pro.

While the logic board and fans are removed, use a can of compressed air and a soft, non-static brush to remove dust and other debris from the upper case and the logic board, particularly from the fan exhaust openings along the rear edge of the upper case.

When reinstalling the motherboard, make sure all cables, and the two rubber heat sink/fan covers, are visible and not trapped under the motherboard.

Second photo, clockwise from top: battery, right speaker, keyboard backlight, AirPort/camera, display, microphone, left speaker, keyboard, and trackpad.