The average office worker spends  28 percent of the workweek managing email. One reason for this insane time suck: Lots of people are using email incorrectly. That's according to Dmitri Leonov, VP of growth at SaneBox, a five-year-old email filtering service that helps users get to "inbox zero," meaning it stashes away all the nonsense clogging your inbox, making it easier to focus on only the messages that actually need your attention. Here's what he says lots of people are doing wrong when it comes to email.

1. Getting sucked in.

From the minute you wake up it's easy to grab your phone and start checking email. While you may get points for trying to stay on top of things, you're really just giving control of your morning to whomever is on the other side of those messages. It's the same thing once you get to work--before you know it, it's noon and you've done nothing other than respond to email. Instead, schedule time for dealing with email, such as every day at 11 a.m. for no longer than one hour.  "Basically the underlying principle here is focus and prioritization," he says. "If email is your number one priority, that means other peoples' priorities are now your number one priority, and that's just a problem."

2. Not using filters.

SaneBox, Gmail Priority Inbox and ZeroMail are just a few of the many tools available that figure out which messages are important and which ones aren't. Essentially, they move things like newsletters, notifications from social media, and marketing messages out of your inbox into separate folders you can peruse at your leisure. 

3. Using the inbox as an archive.

Leaving every single message in your inbox is terrible for your focus and productivity. Ideally, your inbox is clean and every message--once dealt with--is filed into a folder, deleted or archived. In fact, Leonov says you should treat your email inbox the same as you do your physical snail mail box. "Leaving messages in your email inbox is the equivalent of taking envelopes out, reading them and then stuffing them back into your [physical] mailbox. It just doesn't work," he says. "The inbox is really meant for stuff that you have not processed." And don't worry--anything you archive or file will still be findable if you search for it later.

4. Looking at the same emails time after time.

Not every message is actionable right now. If you can't process a message for two weeks, get it out of your field of vision until you can. SaneBox has a snooze function that will remove a message from your inbox until a later time.

5. Including images in a signature.

Graphics behave as attachments and suck up bandwidth unnecessarily. Even seemingly innocuous company logos are bad form. "There's just no need for [it]," he says.

6. Unnecessary emailing.

Can you use another communication medium, such as a company collaboration tool? Will a phone call suffice? What about an in-person conversation? "The practice we adopted at SaneBox is if you need an answer right away, use chat," he says. "If it's an open-ended question or could turn into a lot of back and forth, it's better to just pick up the phone and talk it out."