In a world of instant and on-demand, it feels like there's an ever-growing mountain of tasks to attend. We need to respond to somebody's email, finish up a project tomorrow, and of course, spend time with friends and family -- if there's any time left.

The more work we have in front of us, the easier it is to get into a frantic state of mind. Our brains get frazzled, and we end up working on counterproductive tasks simply because they're in front of us.

The interesting thing about being productive, though, is that it's about becoming selective about what you do -- not stacking on more tasks.

Here are a few things you should stop doing to get more done:

1. Trying to do everything at once

Do you ever see those people who run around trying to do a bunch of tasks and stressing themselves out? They're pulling their hair, running from place to place and barely have time to breathe. They try to do everything and completely panic in the process.

I used to think people like this got more done. That is, until I saw their results. I realized that trying to do everything prevents you from getting really good at anything.

If you want to become better at something, it means saying no to other opportunities --- at least for now.

For instance, top ranked tennis player Serena Williams is into fashion and has her own clothing line. But when she first started out, she focused all her energy on becoming the top female tennis player. Her fashion business came afterwards.

Become the best in one area, and then branch out later.

2. Micromanaging everything

Micromanagement is a common problem for perfectionists who need everything done their way. They tend to hover over other people's work and try to fix things that could have been done more easily by someone else.

The worst part about micromanaging is that other people feel smothered. They feel unappreciated because their work isn't respected.

Instead of looking over every single detail, try to focus more on the big picture. Loosen the reins to give others some decision-making power, to a certain extent. It's better for your health and well-being.

When you learn to let go of some things, you'll find that you can accomplish your more important goals.

3. Just "winging it"

Remember when you had group presentations in school? There was always that one person who brushed it off and announced, "I'm just going to wing it!" Chances are, that person wasn't performing at the top of the class. Even if they were, the person wasn't actually winging it.

High-achieving people are proactive, rather than reactive. They prepare relentlessly and practice daily so that when the time comes, their performance is flawless.

If you want to excel, don't wing it. Focus on the big moment. When you overprepare, you become familiar with what needs to be done, inside and out.

4. Not giving yourself any free time

A common misconception is that successful people work day and night, non-stop. They don't have time for fun or games. Nothing could be further from the truth.

Creative people and innovators often need spare time in order to explore. By taking time to relax, they can reflect on obstacles they face and see them from a different perspective. This can happen whether you're having fun with people, or going for a walk outside after a tiring brainstorming session.

Arianna Huffington herself said that sleep is the secret to success:

"I studied, I met with medical doctors, scientists, and I'm here to tell you that the way to a more productive, more inspired, more joyful life is -- getting enough sleep."

So often, we think that not having any time to rest is a badge of honor that we wear proudly. Instead, we should think about getting more sleep to re-energize, become happier and get more done.

Treat your energy levels like a bank account. Use your efforts wisely and don't forget to rest when you feel that you've come to a roadblock or can't think clearly.

5. Skipping meals and breaks to get more done

A friend bragged to me the other day that she had worked for 18 hours a day, non-stop. She revealed that she frequently forgets to eat because she's so busy.

On the other hand, another friend gets lots of sleep and cooks his own food. He has more spare time to play sports and spend time with people in his life. Guess who got more done at the end of the day?

Skipping meals lowers your energy and concentration levels, so that you get less work done for each hour you put in. It also leads to increased cravings for foods that are quick fixes, like junk food.

I find that preparing most of my meals the evening beforehand helps to set up my day right so that I don't have to look around for something unhealthy to satisfy my hunger. It also gives me one less thing to worry about the next day.

The Productivity Paradox

We see productivity as getting more done, which means spending more time and effort on our tasks. But it's just the opposite. In order to achieve more, you need to focus on less.

Spend your energy on the goals that matter most. Dedicate more time to relaxing. When you're selective with your efforts, you can start living and working in a way that gives you the most value for your time.