Illustrator - duplicate and reflect an object

In Adobe Illustrator CS5, there are often times when you need to copy an object and reflect it (as if its in a mirror). For example, if you are drawing a face then often you need it to have symmetrical features - you might draw one eye and want to duplicate it and flip it to make the second eye. The following steps will help you do this:

1. Select the object (or select more than one object and click Ctrl-G to group them)
2. Press O (the letter "o" for Oscar - or click the Reflect button from the toolbar)
3. Carefully position (do NOT click!) the mouse pointer on the axis of where you want the reflection to be. For example, if you selected one eye, you'd position your pointer in the middle of the face, on or over the nose.
4. Press Alt and keep it pressed, click the usual left mouse button
5. The Reflect dialogue box will appear - click to enable the Preview
6. Click Horizontal or Vertical, on the page you can see what happens, whether your image has been reflected in the direction you need or not. 
7. Click Copy (not OK) for your object(s) to be duplicated and reflected.

More information can be found here:

http://help.adobe.com/en_US/illustrator/cs/using/WS714a382cdf7d304e7e07d0100196cbc5f-62dca.html#WS714a382cdf7d304e7e07d0100196cbc5f-62daa  (last accessed November 2011)