Clutter, both mental and physical, is a productivity and a joy killer. And you don't have to take my word for it. Here's what one study out of Princeton concluded about clutter:

"If you want to focus to the best of your ability and process information as effectively as possible, you need to clear the clutter from your home and work environment. This research shows that you will be less irritable, more productive, distracted less often, and able to process information better with an uncluttered and organized home and office."

So how do you make space in your life for good work and real joy? Nelson Wang has a few ideas. On question-and-answer site Quora recently, the founder of CEO Lifestyle offered a straightforward but powerful 12-step program to simplify your life in response to the question "How can I make my life simpler?" Here are the basics:

1. Simplify your meals.

Sometimes fewer decisions are better. If you don't have to think about the little things, that leaves more mental bandwidth to ponder what's really important. (It's a principle both Mark Zuckerberg and President Obama understand well--both men wear basically the same thing every day for this reason.)

Wang applies the idea to mealtimes. Why don't you automate your breakfast, he suggests. "I used to make a different breakfast every week. One week it would be breakfast burritos, the next week it would be egg muffins. It took a lot of prep work, cooking time, and dish washing. So what did I do? I bought a NutriBullet and now I drink a vegetable and fruit smoothie every morning." Don't like smoothies? I'm sure cereal is fine too. The point is consistency and ease.

2. Every year, clean out your house.

This one couldn't be more straightforward: "Are you using it? If not, toss it out. The less clutter you have, the better," Wang says.

3. Be present in the moment.

"When you do something, really focus on the task at hand and be present. For example, when someone is talking to you, don't work on your computer at the same time. Look at them, really listen, and engage with them," suggests Wang. A whole host of experts agree with him. Even doing the dishes can help you calm and center yourself if you pay full attention to what you're doing, research shows.

4. Use the calendar on your smartphone.

"You're going to have a million things to do. If you put it into your mental checklist, chances are you'll forget it. So put it on your calendar!" Wang urges readers.

5. Learn to say no.

"You can't do everything. Find out what's really important to you and prioritize those activities," Wang sensibly suggests. This one is probably easier said than done, however. Though help is available--there's tons of good advice out there for those who struggle to say no.

6. Arrive for your flight two hours ahead of time.

Another bit of advice that needs no elaboration: "Trust me on this one. After flying to 50 cities in one year, this will reduce your stress a ton!"

7. Do more of what makes you happy.

Again, this is a super simple tip, but it's one most of us could benefit from being reminded of now and again. "Life's short. Don't spend it living someone else's life," urges Wang. It might also help to motivate you to know that living the life someone else wanted for you is one of the most common end-of-life regrets.

8. Slow down.

"When you take your time, you're more likely to enjoy the moment," say both Wang and commonsense.

9. Take an hour to unsubscribe to all the junk mail in your email.

You know it and Wang knows it: "Having to delete junk email every day is a colossal waste of time." Why not spend a few minutes hitting unsubscribe over and over again today and spare yourself a full inbox for months to come?

10. Create an exercise routine.

It doesn't matter which type of exercise you choose, but choose something and stick to it. Having trouble keeping your commitment to exercise? The New York Times has a practical suggestion to help you stick with your fitness goals.

11. Use the 10-year test.

You don't just want to create physical space in your life and blanks in your schedule, you also want to clear up some mental bandwidth to actually enjoy your life. Try this: "Feeling stressed about something that just happened. Use the 10-year test. Ask yourself, will this matter in one year, five years, or 10 years? If it won't, you need to stop stressing out about it. Move forward."

12. Learn to let go and to move on.

Again, harder said than done, but Wang's advice nonetheless bears repeating: "You can't change the past. It's time to move on."