This will be brief.
Inbox zero is a valuable thing to maintain. Roughly promoted around the web as having an empty inbox.
An email inbox collects a few things:
- junk
- automatic mail sent to you
- personal mail sent to you
- work sent to you
- (maybe - work you send to yourself because that's the best way to store information for now)
- Old as all hell (or other friendly name)
- 2014
- 2015
- 2016
There is some implicit training in this process; by the time you have created "very old" and "" you are on the way to sorting things slightly better than you have before; or getting a perspective on "things that have expired or passed". I almost certainly didn't explain that very well.
I can't teach to (2) other than to say that after the activation energy (of setting up the system) it's mostly gone from every-day experience. As for (1) - dealing with things; and having a minor sorting system makes it easier to realise how much there is/isn't. and can help you actually get a handle on it.
Does that help?