Perhaps one of the oldest and most oft repeated chestnuts in the startup world is that you shouldn't fear failure. 

"Failure is an option here. If things are not failing, you are not innovating enough," Elon Musk told SpaceX employees in the company's early days, for instance. 

Or how about this classic from Thomas Edison: "I have not failed. I've just found 10,000 ways that won't work."

Entrepreneurs are bombarded with the message that getting over your fear of failure is essential for success, probably because it's true. But that doesn't make it easy. Failure feels terrible for most normal humans, and it's natural to worry about the social, economic, and business costs of falling on your face. 

But just because fear of failure is hardwired into us, it doesn't mean we can't overcome it. Several iconic entrepreneurs have shared simple, actionable advice on how to grow more fearless so you can dare greatly. 

Elon Musk 

With his rocket ship company and dream of colonizing Mars, Musk may seem like a naturally fearless type, but he's actually previously confessed, "I feel fear quite strongly." How does he overcome that terror? Not, as you might expect, through positive thinking, but through its opposite: fatalism. 

"Something that can be helpful is fatalism, to some degree," Musk explained. "If you just accept the probabilities, then that diminishes fear. When starting SpaceX, I thought the odds of success were less than 10 percent and I just accepted that actually probably I would just lose everything. But that maybe we would make some progress." 

Forcing yourself to look closely at the worst case scenario and exactly how bad that would really be isn't just one of Musk's crazy ideas. Other wise and successful folks, from Tim Ferriss to the ancient Stoics, insisted that facing failure head-on in your imagination can take some of the terror out of it. 

Richard Branson

If ruminating on the worst-case scenario doesn't sound like a good idea for your personality type, then Sir Richard Branson has another suggestion

Like Musk, the seemingly fearless Virgin founder claims to sometimes be anxious just like everyone else. "There were countless times during our record-breaking hot-air balloon trips when I wondered whether we were going to make it back down to earth alive," he has said, for example. 

Rather than focus on how bad a particular negative outcome might be (in the case of a hot air balloon it's death, which seems unlikely to calm any nerves), Branson suggests you focus on learning. Calling failure "one of our greatest learning tools" Branson recommends those in the grip of anxiety think about all the things a seemingly negative experience is teaching them.  

Switching your lens in this way will shift your focus from the short-term discomfort of failure to the long-term gains. That should boost your courage. 

Sara Blakely 

Self-made Spanx billionaire Sara Blakely has made a similar observation about failure: While it feels horrible, it often leads to wonderful things down the road. It's just hard to remember that in the moment. Blakely suggests a short writing exercise can help remind you of this truth. 

"My dad would encourage me any time something didn't go the way I expected it to, or maybe I got embarrassed by a situation, to write down where the hidden gifts were and what I got out of it," Blakely told Business Insider. "I started realizing that in everything there was some amazing nugget that I wouldn't have wanted to pass up."

You could try this too. Next time you've experienced a setback and it stings, get out a pen and paper and try to write out all the positives that are likely to come out of the experience. 

You just might train your brain to think of failure as less of a disaster and more of a steppingstone to greater future success.