A brief summary:
- If you can deal with any email in 2 minutes, do it immediately.
- Only check your email every 30min/hour.
- Create 3 folders for emails requiring more than 2 minutes: answer, read, hold - empty these regularly!
- DON'T organize emails - this takes too much time and is unneccessary.
- DELETE all email once you've handled it. I think this is the real secret. Because virtually every email program/provider offer you the opportunity to never empty the Trash folder, this can become your archive, you can send emails there by just pressing the delete button and if you need to find some thing all you have to do is search for it. I know it's scary, but it's worth it!
I suggest you read the full article here, especially if you're interested in trying it out.