Managing email is a major task. Knowledge workers spend 28% of their time on email.-bakadesuyo.com. Luckily, there is lots of information available on how to handle it. Listed below are a few links to articles I have found helpful.
The four D’s for decision making are similar to the ones for paper management.
Tips for Mastering E-mail Overload by Stever Robbins.
8 Things Email is Good For and How To Keep Your Inbox Empty: 7 Simple Email Tactics from timemanagementninja.com