Like most automation junkies, I like to have quickly accessible commands and hotkeys to perform common functions. For me, my go-to tool of choice is Alfred.
Today's piece of automation was creating a quick workflow to set message colors in Mail.app. Color options are the standard ones that AppleScript supports. Simply, select the messages you want to colorize and either bring up Alfred and use "label <color>" or set the hotkeys for each color and cut out some typing.
Download the Workflow
Before anyone asks, I have used Mail Act-On before. It's a great product, but I generally find I don't use most of the features. For me, a simple workflow does all I need.