The three most important keys on your Mac can be found to the left and right of the spacebar (for right and left handed use). Unfortunately these three keys seem to cause more confusion than any others.
Although there are plenty of people who don't know How to right-click on a Mac...
Where and what is the option key?
There is a great deal of confusion over what Apple often calls the Option key. If you'are using a UK keyboard chances are this is called the Alt key so it's no wonder most people don't know where it is.The Alt (aka the Option key) can be found between Control and Command.
Unresponsive apps? Here's how to ctrl-alt-delete on a Mac, aka Force Quit on a Mac
What's the Command key? I hear you ask...
The Command key has a legacy that leads to confusion. Many will refer to it as the Apple key, because in the past there used to be an Apple logo on it. The logo you will definitely find on this key looks like a squiggly square (?). It was designed by Susan Kare for the original iMac (and based on the Scandinavian icon for places of interest).
The Command (cmd) key works in a similar way to the Control key on a PC. On a Mac you use the Command key where on a PC you would use Control (or Ctrl). E.g:
Command-B = Bold
Command-I = Italic
Command-Z = Undo
Command-Q = Quit
Command-W = Close window
(Read definitions of more Apple-related tech terms in our Apple users' tech jargon dictionary.)
So if you are wondering how to copy and paste on a Mac...
Command-C = Copy
Command-X = Cut
Command-V = Paste
What does the Control key do then?
The most common use of Control is to mimic the right click on a mouse or when using the mouse pad (since some Apple mouse don't have the right click option). However, there are many more uses for Control when used with other key combinations.
Other Apple keys…
Before we get on to these key combinations, there are a few other Apple specific keys (depending on your keyboard).
F1/F2 - Brightness
F3 – Mission Control (for an overview of all running applications, grouping windows from the same application)
F4 - Spaces (which allows you to create and assign a 'space' for different categories of applications – one screen for social networks another screen for real work)
F10/F11/F12 – Sound
How to type letters with accent marks
Some letters can be typed with accents on top, like this é, ä, ö. This is easy to do in OS X, just old the letter down on the keyboard. Above it appears a bubble menu with all the different options. Each accent option has a number below it, tap the number on the keyboard to turn the letter into that accented version.
Read next: Best Mac keyboards
How to type special characters and math symbols
You can use the Character Viewer to find special characters and math symbols. In Finder choose Edit > Special Characters (or press Command-Control-Space). This opens the Character Viewer window.
The Character Viewer enables you to locate any special character from any font on your Mac. Use the sidebar to view different categories, such as Currency Symbols or Math Symbols and double-click any item in the main window to insert it into your document.
You can also search for any option using the Search field in the top-right. Enter a term like "cat" to find all the symbols that are cat-like.
The Character Viewer is placed permanently above all other windows, so you can continue typing in your app and view the Character Viewer on top of its document. You can switch between a small and large Character Viewer using the icon to the right of the Search Field.
It is also possible to add the Character Viewer as a Menu bar icon, this enables you to quickly access it from any app. Open System Preferences, choose Keyboard > Keyboard and select the Show Keyboard & Character Viewers in Menu Bar option. Now you can click on the Character Viewer icon in the Menu bar and choose Show Character Viewer.
Where do I find emoji characters on a Mac?
Emoji characters (small graphics) started out in Japan years ago, but have become more common in recent years. You find Emoji in the Character Viewer. There is a special section called Emoji in the sidebar. Often it's easier to use the Search field in Character Viewer to find Emoji characters.
Alternatively, you can also press Control, Command and Space bar to access the emoji quick select menu. ????
How do I learn shortcuts for OS X keys
One neat trick to learning keyboard shortcuts on a Mac is to use the Keyboard Viewer. Enable the Show Keyboard & Character Viewers in Menu Bar option (in System Preferences > Keyboard > Keyboard).
Now click on the Character Viewer icon in the Menu bar and choose Show Keyboard Viewer. A visual representation of the keyboard appears, and as you press keys they will be highlighted. If you hold down the Alt and Shift keys the Keyboard Viewer shows all the special characters on each key. You can use this to learn the special characters on each key.
Before Expose became Mission Control you could view all the documents open in a particular application, or hide the windows to show the desktop. You still can:
Control-F3 = App Expose
Command F3 = show desktop
Now for some of those keys you can't find…
Alt-2 = Euro sign (€)
Alt-3 = Hash sign (#) (Sometimes called the 'pound' sign)
Alt-: = ellipsis (…)
Alt-G – copyright ©
Used to using a PC keyboard? Wondering how to delete forwards?
Fn-Delete = Forward delete
Alt-Delete = Delete the whole word to the left of the cursor
Taking screen shots and screen grabs?
Command-Shift-3 - Capture the screen to a file
Command-Shift-4 - Capture a selection to a file
Shutting down and 'Sleeping' your Mac
Ctrl-Eject = Show the restart / sleep / shutdown dialog
Shift-Control-Eject = Will put your displays to sleep
Command-Alt-Eject = Will put the computer to sleep
Command-Control-Eject = Save/Quit all applications then restarts Mac
Command-Alt-Control-Eject = Quit all applications then shuts down the Mac
Command-Shift-Q = Log out of your OS X user account (you'll be asked to confirm action)
Command-Shift-Alt-Q = Log out of your OS X user account immediately (you won't be asked to confirm action)
Command-Alt-esc = Force Quit
Command-shift-Alt-esc (for three seconds) = Force Quit the front-most application
Read next: How to lock a Mac
Some other useful key combos to know
Command-Shift-Question Mark (?) – open help
Command-Shift-Delete – Empty Trash
The Application Switcher
Another handy key combo is the one that brings up the Application switcher. This is a handy way to move between different applications you have open.
Command-Tab = Move to the next most recently used application from your open applications
Command-Shift-Tab = Move backward through a list of open applications (sorted by recent use)
Command-~ (Tilde) = Move backward through a list of open applications (only when Application switcher is active)