You might have known about the ability to capture any object on your screen by either pressing (Apple + Shift + 4) to select a portion of your screen, or (Apple + Shift + 3) to take a screen shot of your entire screen. I’m guessing you don’t know the 3rd way to capture items without opening Grab of course. Simply hit (Apple + Shift + 4) but press the Space Bar to enable the selective screen capture tool. Now you can choose what object to take a picture of. Mac OS X already handles the opacity of objects behind it so you don’t need to worry about that. Now you know how to make great screen captures without having to open Grab.