Dennis Kennedy has a great article at LLRX.com entitled The Fourfold Path to Email Enlightenment. I agree with Dennis about keeping your inbox clear, and in that regard I found the email tips in Getting Things Done extremely helpful.
Here are keys: (1) delete all junk right away and filter as much of it as you can; (2) create a couple of folders that you can drag things into and get them out of your inbox; (3) these folders can be called “@ACTION”, “@WAITING FOR”, and “@READ LATER”. The reason for the “@” symbol is to make the folder appear at the top if you are using Lotus Notes or a program that alphebetizes the folders. ALL CAPS makes the folder stand out.
After you have these folders you are set to deal with the onslaught. When you review your email, immediately delete the obvious crap, act on the stuff that you can act on quickly, and move the remaining emails to one of the three folders described above. The “WAITING FOR” folder is for stuff that you will have to act on when you receive a communication from someone else that you are waiting for. “READ LATER” is for stuff you want to read but that isn’t something you have to act on.
“ACTION” is obviously stuff that you need to act on, but which you couldn’t deal with when it first came it. If your “action” items relate to a client file and you have a E-mail folder for that file, then you can drag the E-mail into the client-matter folder after you’ve acted on it.
I have to say that this system is simple, but powerful. And I highly recommend Getting Things Done, which is a great short book on how to organize your life (digital and non-digital). Thanks to Rick Klau for recommending it on his weblog awhile back.