Did you know that you can switch between apps with a key command. Command (⌘) + Tab then release allows the user to switch to the previously used application. If you are doing research between two applications this simple step is great. This interface is more flexible than it seems at first. For instance, if you bring the App Switcher up and hover your cursor over an icon then release “Command (⌘)”, it will go to the application you highlighted.
Also, when you have an application highlighted, you can do a few other things: press Q to quit an app instantly; press H to hide an app from view; or press the up or down arrows to see the highlighted app’s open windows in Mission Control.
One last thing that I find helpful with the App Switcher is that you can scroll back and forth to choose the app you want with your left pinky. Command (⌘) + Tab goes left to right and Command (⌘) + Tilde ( ~ ) will go right to left once the App Switcher is activated.