Fear steals our dreams.

Think about the last time you really longed for something but let fear talk you out of it. Nothing loud or demanding. Just a whisper. A doubt, a shadow. But fear's insidious voice was enough to stop you. Again.

Yet some people seem to be deaf to fear's call. How are they able to move through life without putting up roadblocks of their own construction?

I believe they've learned a secret.

People who thrive and succeed aren't fearless. They suffer from the same insecurities and self-doubts as you and me.

The difference is they've developed a mental toughness. They've learned to take action despite their fears. Not big, heroic, run-into-a-burning-building-and-save-the-baby action, but one tiny action that moves them an inch closer to their dreams.

Katherine Berman and Sophie LaMontagne gave up careers in fashion and venture capital to launch Georgetown Cupcakes (of television fame). They say that as entrepreneurs they're afraid every day, but they've learned to move forward despite their fears. They've developed courage, that mental toughness, and little daily choices over time have made their business successful.

Here are three steps you can take right now to build your own mental toughness:

1. Train

To successfully run a marathon, you can't go from couch to finish line the first week. Your success starts with a single step, followed by another, and then another.

You'll probably be short of breath after running around the block the first time you train. It'll take you months to gradually build your stamina and muscles to ultimately carry you through 26.2 miles.

Courage is no different. It's a muscle that grows with training.

Scott, a management consultant with whom I worked, worried about being seen as too high maintenance if he made requests on his own behalf. From basic things like getting his order right at a restaurant to larger issues like being bypassed for a promotion, Scott's default action had been to suck it up.

When he decided to change, he started small by asking the flight attendant for a fresh cup of tea when he was served a tepid cup. By speaking up for what he needed in a small way, outside of a critical work conversation, Scott started to build his courage muscle in a safer setting.

2. Experiment

Courage fades away if you don't restock it every day. The more often you take courageous action, the easier it is to achieve your daily goals and pick up where you left off the day before.

Don't wait for chance to present you with an opportunity to practice. Just as you schedule workouts, schedule something that scares you. Putting it on your calendar will also force you to think about what genuinely frightens you.

Jia Jiang, the well-known speaker and entrepreneur, decided to immunize himself against the fear of rejection after he was crushed at a last-minute rejection from a potential buyer for his business. He actively sought out situations where he could be rejected for 100 days. Not only did he increase his fearlessness and creativity, but he published a book and won coveted speaking opportunities.

3. Reframe

Often our biggest fear is failure. Instead of looking at failure as a dead end, reframe it as an opportunity to expand your definition of success.

I once had a job as a programmer. A year in, my manager asked me to write code that he and my peers would review for quality.

A couple of hours before the review, my manager called me to his office and said: "I looked at your code ahead of time. We're going to cancel the code review. The quality of your code is not up to par and going through the review will just be an embarrassment to you."

Leaving work early that day was easy; showing up the next morning was the issue.

I was humiliated. Shamed. I had failed and going back to work wasn't going to suddenly make me a better coder.

After encouragement from my husband, I took the first small courageous action: I showed up to work the next day. My manager and I talked. We recognized that coding wasn't going to be my calling, but there were many other technical jobs that were an option.

A month later, I had work that kept me challenged and happy. Failing at coding meant I was available to try other ways to succeed in computer science.

Inspiration to act with courage is all around us--from great leaders to friends to the person in the next office. You can cheer from your seats as you watch them achieve their dreams and still be rooted in your own fears. Or you can achieve your dreams by getting out of your seat and training, experimenting, and reframing.