Many drivers of entrepreneurial success are uncontrollable, including timing, the market, competition, and well, lucky breaks. However, there is one thing you can control--yourself. And according to science, self-control is a key quality in business success. People with high levels of self-control are more effective with their time, thoughtful in their decisions, and productive with their work.

The good news is that self-control, like a muscle, is a skill you can strengthen. Here are four simple ways to increase your self-control:

1. Stop saying "I can't."

The language we use to describe our choices impacts our behaviors. In one experiment on resisting temptations and sticking to goals, participants with health and wellness goals were split into three groups and instructed on what language to use when rejecting activities that put their goals at risk (for example, missing a workout class or eating a candy bar). The first group was told to just say, "no," the second to say, "I can't" (for example, "I can't miss my workout class,") and the third was instructed to say "I don't" (for example, "I don't miss my workout classes."). Researchers found that people who said, "I don't," were significantly more likely to stick to their long-term goals.

The next time you are asked to spend your time in a way that is at odds with your goals, be intentional about the way you turn it down. For example, instead of, "I can't increase the budget for that initiative," say "I don't increase the budget for low-priority initiatives."

2. Get more sleep than you think you need.

According to PhD and The Willpower Instinct author Kelly McGonigal, sleep plays an important role in our capacity for self-control. When we are sleep deprived (sleeping less than six hours each night), our brain functioning in impaired. Specifically, the prefrontal cortex is unable to control regions of the brain that create cravings and respond to stress. But when we get enough sleep (6.5 to 7.5 hours each night, according to a recent study), this impairment in the prefrontal cortex does not exist.

Sleep is often the easiest thing to sacrifice. It may seem like the longer you are awake, the more you get done. But with more sleep--and more self-control-- your ability to discern what you get done and how you do it will be significantly better.

3. Exercise more.

In a recent study by University of Kansas researchers, participants took an initial questionnaire to demonstrate their level of self-control. Then, they undertook a two-month running or jogging regimen, in which they met with researchers three times per week to exercise. At each meeting, participants also retook the questionnaire. Not only did participants have significantly higher levels of self-control at the end of the study, but this effect lasted even one month after the study had completed, suggesting that through exercise, they had increased their self-control.

Whether it's going for a quick run before work, walking home, or signing up for a fitness class, find time to exercise more every week. In addition to demonstrating increased self-control, you'll also feel more healthy.

4. Make your bed every morning

According to psychology, your mom was right. There's an actual benefit to making your bed every morning. According to psychologist and co-author of Willpower: Rediscovering the Greatest Human Strength, we can train our self-control muscle the same way we do our endurance. The same way most of us can't just run a marathon after not having run for years, we can't suddenly expect to be experts in self-control. Instead, it's important to start with a small change that requires discipline. Building this habit will spill into our overall ability to express self-control.

Identify a small, positive change you can make to your daily life. For example reading for ten minutes a day, stretching for five minutes a day, or correcting yourself every time you say, "like," or "um." Achieving these small goals will enable you to boost your self-control over time.

Temptation surrounds us and self-control is not an easy skill. But as you increase your capacity for self-control, you will enjoy the perks of being more successful at work (and a happier and healthier human in general).