If your subject needs more side lighting, or you just wish you had added a sidelight before you snapped the photo, this is a pretty cool way to add the effect back in. In the example shown here, we're applying it to a person, but the technique would work pretty much the same way for product shots as well.
Quick Tip: Duplicating is faster than copying and pasting
I use Option-Command-drag (PC: Alt-Control-drag) to make copies of objects because it's so much faster than copying and pasting. Try it for yourself. Select an object, go under the Edit menu, and choose Copy, then choose Paste (or use the keyboard shortcuts for Copy and Paste: Command/Control-C, Command/Control-P respectively). Now, select an object ...