From random phobias to crippling anxieties, all of us battle with some degree of fear in our daily lives. But imagine how your quality of life would improve if you could overcome your fears. How would it change your life?

Here are four tips for tackling your fears from someone who knows. Jay Platt—the subject of the new documentary, “Living Unstoppable”— was living his dream as a U.S. Marine when a cancer syndrome called von Hippel Lindau (VHL) exploded like a bomb on his life. It caused tumors in his brain and on his spine, as well as kidney cancer and the loss of his left eye. After a personal journey of acceptance, however, Platt went on to accomplish feats many world-class athletes wouldn’t consider, including swimming across the Mississippi River while handcuffed, shackled and blindfolded!

Here are four areas Platt focused on that helped him overcome fear and anxiety in order to rebuild his body, mind and spirit:

• Focus on the joys in life: When you realize it’s not all about you, the annoying voice that tells you to be afraid begins to shrivel and loses its poison. Platt’s family, friends and those to whom he donates money through various charities gives Platt strength.

• Spiritual preparation: Just as Platt trains physically for his feats, he finds it essential to work out spiritually in order to stand up to the fear and anxieties that life’s trials bring. To that end, he surrounds himself with positive messages and positive people.

• Use setbacks as a motivator: When something bad happens, one of the most common responses is fear – fear that it will happen again; fear that you’re less than you used to be; or irrational fear. Platt always knew he’d be a Marine; when he was forced to retire early, he had to recalibrate his entire life. One of his favorite quotes is “What are you doing now?” – it doesn’t matter what you used to be.

• Remember a greater good: When he started experiencing complications from VHL, which first manifested in his left eye, Platt promised God that he’d devote his life to others if he got through the scare. He has kept that promise – his Appalachian Trail hike alone raised $109,000 for charity. According to Platt, staying true to a promise might be the most emotionally solid aid to overcoming fear.