Keeping email well organized is a challenge all of us face. Tags, Flags, and Inbox Zero. This short article isn't going to solve all your email woes, but will give you a quick tip to help you on your way to email nirvana.
Mail.app on the Mac has a nice built in feature called Flags. Using flags helps to categorize and even note the priority of a message. Rather than keep a taxonomy floating in your head, I've written a quick tutorial over at Tuts+ to show you how to give email flags meaningful names.
Check out the tutorial here: Quick Tip: How to Rename Email Flags in Mail.app