Aggressively unsubscribe

Almost every service you sign up to will ask for your email address to uniquely identify you as you. This also gives every service a convenient way of contacting you, which few fail to exploit. You should selectively choose the messages you want to receive on a daily or weekly basis. If it’s not something that interests, excites or informs you, you should unsubscribe from that service. You might be reluctant to do so as you think you might want to hear from that service in the future - you probably won't, unsubscribe.

Filter where possible

It may be possible you cannot unsubscribe to a particular service, either because that particular service is so unscrupulous or inept as to not provide an unsubscribe link. Alternatively, it’s an internal work tool that churns out reports or alerts deemed by someone somewhere to be so important that the entire company must receive them. In this case, you should filter them at source - i.e. using Gmail or Hotmail or whoever is the provider of your email account. This is preferable to configuring rules on your email client as they are often dealt with before your email client can even retrieve them.

Be careful who you email

Emails are like loud noises in a cave - creating an initial email and sending to several people will more than likely result in multiple emails reverberating back to you. Only send emails to people who really need to read them. It can be tempting to copy in Tom, Dick and Harry with an "FYI" but if it’s not critical that they read that email, don’t loop them in. You’re only clogging up their inbox and increasing the chances of “Thanks” emails which will clog up your own inbox in return.

Never reply all unless everything is on fire

Treat “Reply all” the same as standing up in your office and shouting a message at the top of your voice. Replying all should only be used to convey messages such as “Everything is on fire, run for your lives” - nothing less. Under no circumstances should you ever reply all asking everyone else to cease replying all.

Be terse

It’s fine to terse with emails. They don’t need to be bookended with small talk for the sake of politeness. Keep them short and to the point. If you require a task to be actioned - clearly outline what that is and what steps you expect to happen for it to be completed. Make it clear if you require a return email confirming receipt or if an action has been completed. Also, make it clear if you don’t require a returning email.

Use the 2 minute rule

If you can reply to an email in under two minutes, do it immediately. This will clear it from your inbox and your mental to do list. The alternative it is to look at it many, many times and remind yourself that you need to respond to it at some stage. That's needless cognitive load - prioritise action over procrastination.

Don't use your inbox as a to-do list

Use a to-do list instead. When emails sit in your inbox, they are a reminder of all the things you have yet to do - which again is needless cognitive load. Separating your to-do list from all your other emails will also give added prominence to your to-do list.

Practice 'Inbox Zero'

You should aim to have dealt with all your emails at the end of each day by either deleting, archiving, moving out to your to-do or replying to each email. You will have to be disciplined to keep this up but it's only in very exceptional cases that an email can't be dealt with by one of the above.

Don't be a hostage your email in 2018.

Edit: A previous version of this post recommended using unroll.me to monitor your email subscriptions. Turns out they have some rather dubious uses for your data so I've now removed that recommendation.