Hold Command-Option to Instantly Create an Alias of a File, Folder, or Application

You can quickly make an Alias anywhere by holding down the Command+Option keys as you drag any File, Folder, or Application to another location. The original item will stay in place but an alias will be created in the location that you dropped the selection to, try it out yourself.

In this screenshot, I dragged VLC from the Applications folder to the desktop while holding Command+Option and created an Alias to VLC on my desktop (signified by the little arrow graphic in the corner of the icon itself).