If you have been using GNOME 3 and the GNOME Shell desktop then you will undoubtedly find this cheat sheet handy. Finding your way around the desktop without the help of a task bar can be tricky at first. While it is possible to use the mouse for each of these actions, GNOME Shell is tuned for fast keyboard navigation. Learning these keyboard shortcuts will make your transition to the GNOME Shell much easier.
GNOME Shell Keybindings
System (Windows) key: Switch between Activities overview and desktop
Alt+F1: Switch between Activities overview and desktop
Alt+F2: Pop up command dialog
Alt+Tab: Application switcher
Alt+Shift+Tab: Cycle in reverse direction in the application switcher
Alt+[key above Tab]: Switch between windows of the same application in Alt+Tab
Ctrl+Alt+Tab: Pop up accessibility switcher
Ctrl+Shift+Alt+R: Start and stop screencast recording
Ctrl+Alt+Up/Down arrow: Switch between workspaces
Ctrl+Alt+Shift+Up/Down arrow: Move the current window to a different workspace
Keybindings can be viewed and changed from here: User Menu -> System Settings -> Keyboard -> Shortcuts
For more information check out the official page:
http://live.gnome.org/GnomeShell/CheatSheet