That's going to be a quick one. If you do any product photography, you can add interest to your photo by using your phone or tablet. Set the shot the way you want it initially making sure you have a long exposure going on (couple seconds). Now it's the time to make your device shine (literally). Display a white image on it and paint light in your shot by experimenting how you move it (or not move it) when the photo is been taken. It adds too much or too little light? Easy, change the screen's brightness accordingly.

Cheers,

Tristan