Learning, keeping track, and remembering every keyboard shortcut for every OS X app is near impossible. While there are ways to figure out whatfor some apps, those methods aren't always convenient to access.
CheatSheet is a small OS X app that runs in the background and will show you all the keyboard shortcuts for whatever app you're currently using.
Getting started with CheatSheet is easy; just make sure you're running OS X 10.7.
- Download and install CheatSheet. It's free.
- Unzip and move the app into your Applications folder.
- Double-click the app to run it.
- Hold the Command key on your keyboard to see keyboard shortcuts for the app you're currently using.
You may notice there's no way to access the app from the menu bar, and double-clicking on the app in the Applications folder doesn't reveal any sort of preferences menu. Should you need to quit the app, you'll need to launch CheatSheet by holding down the Command key and then clicking on the gear icon in the lower-right corner. You can then print a particular list of shortcuts, check for updates, or quit the app.
(Via: OS X Daily)