Just made the switch from a Windows PC to a shiny new Mac? Here are 20 keyboard shortcuts you need to know.

1. Get info

While Cmd + I brings up the Get Info window in Finder, showing things like its location, name and size, adding the Option key will bring up a single Get Info window.

This will update automatically when you click on a different file or folder or select multiple files and folders.

2. Close window

To close a window using the keyboard, simply enter Cmd + W while on the active window. This shortcut proves to be very useful if you want to quickly close a particular open document without quitting the application completely.

It also works for closing individual tabs in Safari. In fact, you'll find it works in nearly every application on the Mac.

3. Show/hide the Dock

How often have you wanted to get rid of the Dock so you can give yourself more room on your screen, but didn't want to go through all the menu options to hide it?

If you press Cmd + Option + D, this shortcut will niftily toggle between hiding and revealing the Dock.

4. Take screenshots

How many times have you tried to describe an error message you're getting, only to be faced with confusion?

Why not take a screenshot, then mail the image instead? Cmd + Shift + 3 captures the whole screen, while Cmd + Shift + 4 gives you crosshairs.

5. Hide application

If you press Cmd + H this will instantly hide all the windows of the application that you're working with.

Also, if you hold down Option as well, it will hide all the applications except the one you're working on, getting rid of all that annoying screen clutter.

6. Application switcher

The Application switcher saves you from having to go to the Dock to change the application you're using.

Keep pressing the Tab key to step through which application you'll switch to (Shift reverses the direction), or point with your cursor to select one.

7. Zoom in/out

This function will need to be enabled in the Universal Access pane in System Preferences first, but once it's activated it will enable you to zoom in or out of the screen.

If you press Cmd + Option + +/-, this will Zoom in or out of the screen and you can then move the mouse to easily pan around the page.

8. Force Quit

If an application has annoyingly locked up and all you get is the dreaded spinning beach ball when you mouse over it, simply press Cmd + Option + Esc. Use this shortcut to bring up the Force Quit dialog – this will then enable you to stop the application with extreme prejudice…

9. Dictionary

You will find that in most OS X programs if you're unsure of the meaning of any word, you can hold down Cmd + Ctrl + D while hovering the cursor over it. This will then handily bring up the OS X dictionary definition of the word and put you back in the know. This tip is for OS X 10.5 only.

10. F9, F10 and F11 – Exposé

Exposé will become even more of a lifesaver if you learn its keyboard shortcuts. These are typically F9, F10 and F11 although you'll find that this is different on later MacBooks. You can also use Tab to cycle between windows or press Esc to exit Exposé.