Once you commit to the Task Switcher in Mac OS X, it quickly becomes an essential tool in your workflow. With it, you can easily switch among open apps.
To call up the Task Switcher, hit Command-Tab and then while still holding down the Command key, you can hit the Tab key repeatedly to cycle through the icons in a rightward direction. If you have many apps open, however, it might be quicker to move to the left to make you desired app switch. Moving to the left is also useful if you overshot your intended app and want to jump back one spot instead of looping around to the right again. To move left through the Task Switcher, you have three options.
1. Left arrow key
After calling up the Task Switcher, you can use the left and right arrow keys (while still holding down Command) to navigate back and forth.
2. Command-Shift and Tab
Use your right hand to hold down the Shift key after calling up the Task Switcher and you can Command-Tab leftward.
The tilde (~) key is conveniently located directly above the Tab key. After calling up the Task Switcher, you can use it (while still holding down Command) to move to the left.
(Via Cult of Mac)