How many times has this happened to you? You're working hard. Feeling productive. You look up, and the clock says 5 p.m. You have no idea where the day went. And despite knowing you were working, the last eight hours seem to be just a giant blur.

If you're like most people who spend their days working online, those days probably have  a lot to do with email.

In fact, a 2012 McKinsey report found employees spend approximately 28 percent of their time responding to, reading, or writing emails. The average worker checks their email upwards of 70 times per day, with the most email addicted of us checking in a ridiculous 350 times.

While email has become the glue that holds companies together, it also is  one of our biggest distractions. So, if you want to get more done each day and stay out of your inbox, here are techniques used by some of the most productive people.

Best-selling author Cal Newport schedules his "deep work" a month in advance

Cal Newport, best-selling author of Deep Work, understands the importance of not letting email take over his day. Which is why he prioritizes meaningful work sessions over checking email by scheduling these sessions months in advance. He says:

At any given point, I should have deep work scheduled for roughly the next month. This four-week lead time is sufficiently long enough that when someone requests a chunk of my time and attention, I've almost certainly already reserved my deep work blocks for that period.

I can, therefore, schedule the request with confidence in any time that remains.

The idea is that instead of fitting your important work around urgent tasks like checking email or taking meetings, you switch priorities.

Superbooked CEO Dan Mall sets dedicated email check-ins on his daily calendar

Designer, creative director, and CEO Dan Mall recently discovered he was receiving 220 emails every single work day (and that's not including spam or newsletters). They were taking over his day. So he decided to set aside two dedicated blocks of time during his day to check email, Twitter, and Slack.

More importantly, these blocks take place after time spent on meaningful work:

"By doing meaningful work for the first 60 to 90 minutes of your day, no matter what happens later that day, you will have advanced your personal mission," he explains.

Designer Jessica Hische answers the bulk of emails on Mondays

The flow of email never stops. So instead of being a servant to her inbox, acclaimed designer Jessica Hische sets one day a week aside for only admin and email. She says:

If I give myself one day to do the bulk of my emailing/interview answering/file organizing/scheduling, etc., I feel way less guilty about ignoring all of that stuff for large periods of time during the rest of the workweek.

You can choose whatever day works best for you, but the goal is to allow your inbox to overflow, knowing you'll get through it on that day.