Command-Tab is probably seared into your muscle memory to switch between running applications while on your Mac. I know it is permanently stuck in mine.
You probably also know that Command-Tab can also be used to quit apps as well, right? And hide apps? To be honest, I knew the first tip, but not the second one, which (to me) makes it worth a share.
First up, when you hit Command-Tab on your keyboard, you’ll get the nice icon bar across the middle of your Mac’s screen, showing you all the apps that are currently running. If you release and re-hit the Tab key while still holding the Command key down, you’ll move the selection square to the right. If you release, you’ll go to that application.
If you release the Tab key and hit the tilde key (~) while keeping the Command key held down, you’ll move the selection square to the left, reversing the direction. Let go of both keys to go to that app.
Now for the fun part. If you release Tab and then hit the Q key, you’ll quit the app that’s currently in the selection square.
If you release the Tab key and then hit the H key, you’ll actually hide the app that’s currently selected. You won’t switch to it, either. Pretty slick, if you ask me.
Via: Stack Exchange