So I'm looking at a somewhat neglected email box now, and I'm going to get it to zero.
First, when an email doesn't need attention (I already answered it, I don't care about it, it was an FYI and I shrugged) I leave it "read". If an email needs attention but I'm not going to process it now, I mark it as unread after reading it. Obviously if I haven't read it, I haven't read it. So when I sit down to do this, I have a mix of read and "unread" emails. I keep up with at least glancing at email, so I know that anything older than the last day I worked is not truly "new", it's just glanced-and-marked-unread.
Anyway, right now I:
- Drag everything that's read (not displayed in boldface, in my email client) into my unsorted email archive for the year.
- Sort the remainder by "from" because it's easier to find junk that way.
- Do "mark as read" on assorted junk--announcements of new training titles, notifications from systems where I know that the notifications are never for me, etc. Move them to the unsorted archive. If there were any actual junk mail, I'd delete it, but the corporate filters seem to do a good job on that.
- Scan what's left. There are some actual tasks in there, though some are as unrefined as "Think about 3/12 email from Fred".
- Open Jira, which is where I'm keeping my work lists right now. At high speed, create tasks, type in a rapid summary of the email (rarely more than about ten words; if I'll need more I'll note the date and sender of the email and go look at the email when I get to the task) and mark those tasks so that they appear in the Backlog for my "MyBoard" board. (Most will be demoted to Someday/Maybe but I want to at least glance at them before that.) Mark those emails Read and put them in the archive.
Inbox is empty. On another day, there might have been some email relevant to my personal system, such as something telling me where to go find my W-2. If there had been, I would have forwarded them them to my personal email address and marked/archived the work copy.
I move email from email to Jira with limited processing because I find tasks much easier to process in Jira. The work isn't really fully processed, but my email is clear, and Jira is nicely predigested for better processing later.