Add a video monitor to your arduino via serial !! You can use it as your prefered output or as a secondary screen for the results of your sketch.
All you send through the serial will be printed out on your TV screen. (You can use an old TV).
On Arduino, you must connect TX from arduino to RX (blue borne) of this my rig adapter. Or on a PC, you can connect direct via USB cable.
Remember, this is just a tool.