Americans aren't strangers to putting in their time on the job. A 2014 Gallup poll found that 40% of U.S. employees work over 50 hours each week, while 20% work more than 60 hours a week. Furthermore, according to the U.S. Bureau of Labor Statistics, the average American works 8.8 hours a day.

But just because you're physically sitting in an office doesn't mean you're making good use of that time. In fact, recent data suggests that despite the amount of time most of us spend at work, the typical employee is only productive for about three hours a day. Ouch.

Employee holding up "help" sign

IMAGE SOURCE: GETTY IMAGES.

Of course, the less productive you are at the office, the more likely you'll be to feel the pressure when deadlines loom and your workload starts piling up. With that in mind, here are a few ways to improve your productivity -- and reduce your stress in the process.

1. Do your least favorite tasks at the beginning of the day

Perhaps your boss insists on a daily account summary that you happen to hate compiling. Or maybe part of your job involves number-crunching, and you much prefer the creative stuff. No matter the dreaded task at hand, most of us have at least one work-related chore we'd put off indefinitely if we could. But rather than push that task off till the last possible minute, make it the first thing you do at the start of your day. This way, you'll have more mental energy to conquer whatever it is you detest doing -- as opposed to eight hours later, when your mind is slowly turning to mush. Once you're able to check that loathsome task off your list, you'll be able to approach the rest of your day with a clearer head.

2. Power through, but take breaks

Just as working too many hours can actually start to derail your productivity, so too can plugging away without a pause render you less efficient after some time. But you don't want to fall into the trap of taking too many breaks, either, because not only will they eat up some of your actual time, but they might also interrupt your train of thought. A better approach is to power through for as long as you feel your brain can handle a given task, and then take breaks after accomplishing certain key goals.

Here's an example. Say you're given a week to work on a 10-slide presentation, and you know each slide will take about an hour to put together. You're also convinced that you can't hammer out more than one slide at a time without a break. If you designate a number of hour-long blocks throughout the week, and follow them up with 10-minute breaks that you expressly work into your schedule, you'll be nicely positioned to knock out that presentation in time for your deadline.

3. Lock yourself in a quiet room to avoid distractions

Whether it's the constant dinging of your email, your ringing phone, or the coworkers who can't seem to tear themselves away from your desk, the more on-the-job distractions you're subjected to, the less productive you're apt to be. Rather than let those interruptions detract from your efforts to get your work done, eliminate them periodically as your schedule and office environment allows.

For example, if your office has private conference rooms, and you're able to book one for two hours a week, use that time as an opportunity to do some disturbance-free work. Don't tell your colleagues what room you'll be working from, and take only your laptop if possible, so that your cellphone doesn't distract you from what you're trying to accomplish. Once you're set up in your private room, unplug the phone if there's a landline in there or turn off its ringer. And then use that time to hammer out the tasks that require the most concentration.

If your office doesn't offer the option to occasionally hide out in a conference room, try asking your manager to work from home once a week to achieve a similar goal. If you can prove that this flexibility makes you more productive, chances are, it's a privilege you'll be allowed to uphold.

4. Schedule your meetings strategically

In the business world, there's perhaps no greater productivity zapper than meetings. According to The Muse, middle managers spend a good 35% of their time in meetings. For upper management, that figure climbs to 50%. But if you're smart about scheduling meetings, you'll carve out more time for actual work and spend less time rotting away in conference rooms.

To start, be more selective about the meetings you agree to attend. Unless your presence is absolutely required, learn to say no if you have pressing obligations that make for a better use of your time.

If you have a day with multiple meetings, schedule them back to back, as opposed to with small breaks in between. This way, you'll get them done in one fell swoop, and you'll be left with longer chunks of time to work on other things. Better yet, designate one day a week as your "meetings day" and leave the other four days free, so to speak. This will help you better manage your time so you're able to do more at the office.

Feeling productive is essential to your work-related happiness. Follow these tips, and you'll enjoy a much less stressful on-the-job existence. And who knows? If all goes really well, you might even land a promotion by stepping up your game.

The Motley Fool has a disclosure policy.