Whether it's finally screwing up the courage to put in for that promotion, taking the leap into entrepreneurship, or even getting up the nerve to ask the love of your life to marry you, seizing most big opportunities in life requires bravery. And lack of courage is what leads to our most painful regrets.

Which leaves lots of folks thinking that they'd be more successful and happier if they were a little more courageous.

But psychology shows bravery isn't something we're either born with or we're not. It's a muscle that you can strengthen with practice. In a recent article for UC Berkeley's Greater Good Science Center Kate Swoboda, the author of the book The Courage Habit, suggested exercises to help you build up your courage. Here are three simple ones to get started on today.

1. Get to know what fear feels like. 

Fear is what stops most of us from being braver, but what exactly is fear? If you look closely at what we mean by the term, you'll observe a set of physical feelings -- sweaty palms, a racing heart, a tight knot in your chest. Swoboda insists that if you examine those sensations, you can learn to tame them.

"Once our bodies head into fear mode, we need a way to recognize the signs and work with what the feelings are telling us. A body-based practice can help," she claims. "Using focused breathing or body scans--both practices associated with mindful meditation--can help us tune into our body's sensations without trying to change them or judge them. In this way, we can access our fear without rejecting it or being pulled into an old fear routine."

2. Use writing to calm your inner critic.

Physical panic can stop you from pursuing your deepest dreams, but so can that nasty voice inside your head that tells you you'll never succeed, people will laugh at you, or you're not good enough. Most of us try to ignore or talk back to our inner critics, but Swoboda suggests another strategy.

"If we can take time to listen to our inner critic without attachment--without the need to ignore or accept what it is saying--we're in a better position to learn from it," she writes. "Expressive writing... can help us to understand the origins of our critical thoughts and to glean helpful information without getting hijacked."

3. Build a courageous community.

No one is brave in a vacuum. Humans are social creatures and we draw our strength from others. If you want to be courageous enough to change your life, start by consciously choosing to spend more time around those that bring out your bravery.

Swoboda quotes Charles Duhigg, author of The Power of Habit : "For most people who overhaul their lives, there are no seminal moments or life-altering disasters. There are simply communities--sometimes of just one other person--who make change believable. Making change is simply easier when we have support."

If you're interested in learning more, both the complete article and Swoboda's book offer lots more details.