One of my ABSOLUTE favorite things to do in Photoshop is to play with lighting effects. Whether that be to make something glow, create a spotlight sort of effect, or set my hands on fire, I'm always so impressed with the many ways Photoshop allows you to alter lighting. Because of the skills I've gathered for bending light to my will, I no longer look at an image I've taken and think, "Oh man, I wish I would have brought some flash equipment with me so there could be light spilling through the archway from behind her." I now just think, "Wouldn't it be simply fantastic to have some magical light coming from behind her? Yes, yes it would ... I think I'll add some." Don't get me wrong it's always going to look better if there was actually some real light falling on your subject from the get-go, but that's not going to stop me from adding a bit of illustrative oomf to my images whenever I see fit!