Rule #1, keep your inbox small by using filters and moving messages to folders.
Use rules or filters to move messages, send automatic replies, highlight important messages. Use folders for message groups, immediately put messages there. Highlight with color those must read messages. Set up automatic responses for information requests.
Rule #2, use proper email etiquette.
Understand and use the appropriate addressing fields, including blind carbon copy (BCC). With the “To” and “CC”, all recipients see all other addresses, whereas with “BCC”, only that recipients address shows, not all of the others that you put in BCC.
Hint: You could make a rule/filter that moves messages with your name in BCC to folder called BCC or “not really to me.”
Use good subject line and keep messages to the subject. Remember that email may not stop and stay with the person you sent it to. Try putting questions on separate line, makes it stand out and easier to reply. Send URLs rather than whole web page, or copy and paste the important parts and put links to page at bottom of message. Be careful with attachments, not just because some distrust them, but not all people can view a Word document, for example. Style your message according to your audience and content, think about white space, color, size, etc., but try not to get too fancy.
Rule #3, remember to back up your email and address book.
If you live and die by email, back it up and don’t forget to include your address book. Of course, if you use something like Hotmail or Gmail via the web, then you rely on them to keep backups. But, people have been known to loose email in those systems. So, save it if it is important.
Rule #4, sometimes a phone call is better.