A little over 40 years ago, I began my quest to be a Navy SEAL. Little did I know that the lessons I learned in basic SEAL training would serve me so well throughout the rest of my life. These lessons were simple, powerful tools that helped me deal with the challenges we all confront at some point. I offer them today in hopes that my experience will make your life a bit more productive, a bit more fulfilling, and just maybe, a bit more successful.

The US Navy SEAL’s Basic Underwater Demolition/SEAL (BUD/S) course is considered some of the toughest military training in the world. The schoolhouse is located in Coronado, California, and the training is six months long. The course is divided into three phases. The first phase is 10 weeks long and is designed to weed out the weak of mind and body.

Every day is a test of your endurance. You begin early in the morning with an hour of calisthenics followed throughout the day by a series of long runs in the soft sand, freezing swims in the ocean, body-wrecking obstacle courses, and endless harassment by the SEAL instructors.

During First Phase comes the notorious Hell Week. Hell Week is six days of no sleep, constant harassment, and physical activity. This is where you decide if you really want to be a Navy SEAL.

Second Phase is eight weeks long and equally punishing. It includes more physical hardships, but it is in Second Phase that the student learns to dive the basic self-contained underwater breathing apparatus (SCUBA) and the more advanced closed-circuit breathing apparatus known as the Draeger.

The physical challenges continue as you enter Third Phase, but for the remaining 10 weeks, the aspiring SEALs learn all the intricacies of land warfare: how to shoot, move, and communicate.

From the moment I arrived as a student at the BUD/S compound in Coronado, the SEAL instructors found opportunities to teach you. Every morning, we were required to muster in our barracks room to stand inspection. I stood at rigid attention as the SEAL instructor entered the room. All Vietnam veterans, the instructors had an air of invincibility about them. They had survived a difficult war and knew what it took to be successful in combat.

After checking my uniform to ensure it was immaculately clean, pressed to perfection, and worn with pride, the instructor leaned over to inspect my bed. I remember thinking it was childish to have a combat veteran inspect my navy “rack” to see whether it had been properly made.

We had exacting instructions. The pillow must be centered precisely in the middle of the headboard. The spare wool blanket had to be folded in a rectangle and situated precisely at the foot of the bed. And the corners, at the bottom of the rack, had to be precisely at a 45-degree angle. If we failed to meet the exacting standards set by the instructors, you would pay the price with more physical harassment.

At the time, the lesson of making my bed was lost on me. But the importance of this simple assignment soon became clear. Making your bed was the first task of the day. If you did it well, you took some pride in the task, and that inspired you to do another task and then another and another.

By the end of the day, one task completed had led to many tasks completed. And, if you had a miserable day, you came home to a bed that was made, that you made. And a made bed gave you hope that tomorrow would be better.

Making your bed also reinforced the fact that the little things in life matter. My instructors used to say, “If you can’t even make your bed right, how will we ever trust you to run a complex SEAL mission?”

If you do the little things in life right, the big things will come naturally. So, if you want be successful in life, start off by making your bed.

During First Phase, the students were divided into boat crews. These boat crews were seven men each and generally arranged by height. We were called boat crews because everywhere we went, we were required to carry an Inflatable Boat Small (IBS). The IBS was an eight-foot rubber raft. Fully inflated, it weighed about 100 pounds, and the seven students in the boat crew would lift the raft onto their heads and carry it with them on soft sand runs—to dinner and during physical training exercises. It was our constant companion.

We also paddled the boat endlessly from north to south along the coastline and through the pounding surf, seven men all working together to get the raft to its final destination.

But we learned something important on the journey with the small boat. Occasionally, one of the boat crew members was sick or injured and unable to give it 100 percent.

I often found myself exhausted from the training day or down with a cold or the flu. On those days, the other members picked up the slack. They paddled harder. They dug deeper. They gave me their rations for extra strength. And when the time came, later in training, I returned the favor.

The small boat made us realize that no man could make it through training alone. No SEAL could make it through combat alone, and by extension, you need people in your life to help you through the difficult times.

Everyone has difficult moments in life. Throughout the course of my career, I was fired from a very important job; I was senior officer in charge when we lost a 33-foot boat in heavy surf; and I was seriously injured in a parachute accident.

On each of these occasions, someone came to my aid. My wife, my boss, my friends, people I didn’t even know, all helped me because they saw I was in need.

None of us is immune to life’s tragic moments. Like the small rubber boat we had in SEAL training, it takes a team of good people to get you to your destination in life.

You cannot paddle the boat alone. Find someone to share your life with. Make as many friends as possible, and never forget that your success depends on others.

Men from throughout the navy came to SEAL training. They were from small towns and big cities. They were black and white and brown. They were rich and poor. They were as diverse in background, color, size, and strength as any group of men ever assembled.

At the beginning of training, our class had 155 men. By the end of Hell Week we were down to 55 men and soon thereafter, about 42 men. The 42 men were divided into six boat crews of seven men each. I was in the boat with the big men. But one of the boat crews had the little guys. None of them was over about 5 feet 5 inches. We called them the munchkin crew after the little men from the movie The Wizard of Oz.

The munchkin crew was comprised of one Native American, one African American, one Italian American, one Polish American, one Greek American, and two tough kids from the Midwest.

We big guys would always make good-natured fun of the little guys. They wore these “tiny little wet suits,” and they had “tiny little flippers” to go on their “tiny little feet.” But the little guys were not intimidated. They outswam, outran, and outhustled the big guys almost every time.

SEAL training was a great equalizer. Nothing mattered but your will to succeed—not your size, not your color, not your background, and not your social status.

If you want to succeed in the world, measure people by the size of their heart, not the size of their flippers.

In SEAL training, the instructors are kings. Their word is gospel, and a student must do as the instructor says. No questions asked. If an instructor is having a bad day or just doesn’t like the look of your face, he will order you to “hit the surf” and make yourself a “sugar cookie.” The student will dutifully run over the sand dunes to the beach, jump in the ocean, get out soaking wet, and then roll around in the dunes until every crevice in his body is filled with sand. In all of SEAL training, there was nothing more uncomfortable than being a sugar cookie. There were a lot of things more painful and more exhausting, but being a sugar cookie tested your patience and your determination, and not just because you spent the rest of the day with sand down your neck, under your arms, and between your legs, but because the act of becoming a sugar cookie was so completely indiscriminate.

To many of the SEAL students, this was hard to accept. Those who strived to be the very best expected that they would be rewarded for their stellar performance. Sometimes they were and, then again, sometimes they were not. Sometimes the only thing they got for all their effort was wet and sandy. SEAL training taught you that life is not fair.

In today’s world, it is easy to blame your lot in life on some outside force, to stop trying because you believe fate is against you. It is easy to think that where you were raised, how your parents treated you, or where you went to school determines your future.

Nothing could be further from the truth. The common people and the great men and women are all defined by how they deal with life’s unfairness: Helen Keller, Nelson Mandela, Stephen Hawking, and Malala Yousafzai.

Sometimes, no matter how hard you try, no matter how good you are, you still end up as a sugar cookie.

If you want to be successful in life, don’t complain. Don’t blame it on your misfortune. Stand tall, look to the future, and drive on!

Everything in SEAL training is measured. Your long runs and swims are timed against the clock. Your body position has to be exacting during your push-ups, pull-ups, and flutter kicks. Academic tests are scored and must meet a certain threshold. Any failure to meet the standards results in extra physical training. It’s called a “circus.”

The circus comes at the end of the day, after all of the other students go back to the barracks. Those in the circus remain for another two hours of physical harassment. The circus is punishing, and the extra physical training tires you for the following day. One circus can lead to another and another and another.

Worse, the circus has a psychological effect on the student. It’s a recognition that you failed, and to men who rarely failed in their life, it can be overwhelming. The result is a “death spiral” of fatigue and failure that can end a student’s hope of becoming a SEAL.

But, for those who overcome the circus, the extra physical training makes them stronger, faster, and mentally tougher. For those who see failure as an opportunity to learn, to improve, to be humbled by the experience, the circus is a necessary path to success.

In my career, I failed numerous times: hostage rescues that went awry, disastrous raids, and unexpected casualties. But each time, I learned from the failures. I was stronger from the experience and more able to conduct the next tough mission. Life is full of failures. To be successful, you must learn to overcome the circuses.

In SEAL training, there is an obstacle course. It consists of about 25 challenging wooden structures that must be negotiated in a timed run. These obstacles include a cargo net that you must scale and climb over, a lengthy barbed wire mesh that straddles the ground forcing you to crawl under it, a series of walls you must hurdle, and a long rope bridge that you must traverse—just to name a few.

But the most challenging obstacle is the “slide for life.” To successfully complete the obstacle, a student must climb a 30-foot-high tower. At the top of the tower is affixed a long rope that extends 80 feet to another smaller tower at the end of the obstacle.

Beneath the slide for life is nothing but sand. Falling off the obstacle can cause serious injury and likely failure to complete the SEAL training. It is a risky event, and most students move very carefully and deliberately when trying to slide down the rope.

The SEAL training record for completing the obstacle course had stood for a number of years. The only way to beat the record was to assume risk on the most difficult barriers—the only way to stand out above the average student was to go down the slide for life headfirst.

A student’s ability to rise above his fears, to take risks, and to challenge the obstacles was key to completing SEAL training. It’s just like life: If you want to be successful, you must overcome your doubts, face your fears, and confront the peril, for nothing truly worthwhile comes without risk.

Toward the end of SEAL training, the students travel to San Clemente Island off the coast of San Diego. At the island, we undergo another three weeks of infantry-like training, learning to shoot, move, and communicate. It is also at San Clemente where the students conduct some of their most grueling physical tests. One such test is the long night swim.

It was not the distance of the swim that was challenging, for we had swam long distances before, but it was the nature of our seagoing companions that created the concern. The waters off San Clemente were the breeding ground for the great white sharks, one of the largest man-eaters in the ocean.

The SEAL instructors loved to strike fear in the hearts of the students by showing pictures of the massive creature leaping out of the water to devour some unsuspecting California sea lion. There was something unnerving about being alone, at night, in the middle of the ocean, knowing that lurking beneath the surface was a prehistoric animal just waiting to bite you in half. But all the students wanted to be SEALs so badly that nothing in the water was going to stop them.

If we had to fight off the sharks, then every man was prepared to do so. Our goal, which we believed was honorable and noble, gave us courage, and courage is a remarkable quality. If you have courage, nothing and nobody can stand in your way. But without courage, others will define your path forward.

Without it, you are at the mercy of life’s temptations. Without courage, men will be ruled by tyrants and despots. Without courage, no great society can flourish. Without courage, the bullies of the world rise up. But with courage, you can accomplish any goal. To be successful in life, you will have to find the courage within you to swim with the sharks.

During Second Phase of training, you learn to dive the closed-circuit breathing apparatus. It is the frogman’s secret weapon, a diving rig that gives off no bubbles.

But to be a Navy frogman, worthy of the great heroes that came before you, you must become an expert in underwater ship attacks.

At night, under a ship, the darkness consumes you. The light from above is completely blocked by the imposing steel vessel. Your body disappears in the blackness, and the roar of the ship’s machinery confuses and disorients even the most experienced diver.

Under the ship, when things are the darkest, is when you must be at your very best. You must reach deep inside and call upon every strength you have to complete the mission. Being strong in the dark moments is what sets you apart from all others.

There is no darker moment in life than losing a loved one, and yet, during the wars in Iraq and Afghanistan, I watched time and again as families, as military units, as towns, as cities, and as a nation, how we came together to be our best in those tragic times.

I remember vividly when a fallen Army Ranger was returned home to his base in Savannah, Georgia. His entire unit, dressed in their finest uniforms, marched from the church to the Ranger’s favorite bar on River Street. All along the route, the town of Savannah turned out. Firefighters, police officers, veterans, and civilians from all walks of life were there to salute the young soldier who had died heroically in Afghanistan.

At some point in life, we will all confront a dark moment, a seemingly insurmountable challenge, a dark moment that crushes our spirit and leaves us wondering about life’s meaning. To be successful in life, you must reach deep inside yourself and be your very best in that dark moment.

Hell Week. The name itself invokes fear and rightfully so. During SEAL training, Hell Week is the most demanding six days in your young life. You are constantly cold, wet, and miserable. Your hands and feet swell to twice their size from constant movement. The instructors never stop harassing you, and the pressure to quit is unimaginable.

But one day in particular separates the winners from the losers. It’s Wednesday at the Mud Flats.

The Mud Flats is an area between San Diego and Tijuana where the water runs off and creates the Tijuana slues, a swampy patch of terrain where the mud engulfs you. As the sun began to set that Wednesday evening, my class was ordered into the mud. The mud consumed each man until there was nothing visible but our heads.

The night wind howled across the beach making the mud colder as each minute passed. The instructors, bound and determined to find more weak souls, stood on the edge of the mud and offered to comfort the rest of the class if only five men quit—just five men, and the rest of the class could leave the oppressive mud. It was clear that some students were ready to quit. The mud was unbearable.

And then, one voice began to echo through the night. One voice raised in song. The song was terribly out of tune but sung with great enthusiasm. One voice became two and two became three, and before long, the entire class was singing.

The instructors threatened us with more time in the mud if we kept up the singing, but the singing persisted. And somehow the mud seemed a little warmer, the wind a little tamer, and the sunrise not so far away.

If you want to be successful in life, you have to give people hope. The power of one person—a Washington, Lincoln, King, Mandela, Malala, or you—with the power of hope, can change the world forever.

Finally, in SEAL training there is a bell, a brass bell that sits in the corner of the compound. All you have to do to quit is ring the bell. Ring the bell and you won’t have to get up early. Ring the bell and you won’t have to do the long runs, the cold swims, or the obstacle course. Ring the bell and you can avoid all the pain that comes with SEAL training.

Of all the lessons I learned in SEAL training, this was the most important: Never quit! It doesn’t sound particularly profound, but life constantly puts you in situations where quitting seems so much easier than continuing on. Where the odds are so stacked against you that giving up seems the rational thing to do.

If you want to change the world, if you want to be successful in life, follow your dreams and never, ever give up.

My lessons are simple ones:

• Start every day with a task completed.
• Find someone to help you through life.
• Respect everyone.
• Know that life is not fair and that you will fail often.
• Take some risks, step up when the times are toughest, face down the bullies, lift up the downtrodden, and never, ever give up.

If you do these things, then none of life’s challenges can stop you from achieving your goals and, at the same time, making the world a better place.

Admiral William H. McRaven, USN (Ret.), is a retired U.S. Navy four-star admiral. Most recently, he served as the University of Texas system chancellor. McRaven has been recognized for his leadership numerous times by national and international publications and organizations. Prior to becoming chancellor, McRaven was commander of U.S. Special Operations, where he led a force of 69,000 men and women worldwide.