The 7 Habits of Highly Successful People by Stephen Covey was first published in 1989, and has since sold over 25 million copies. The book provides a roadmap for attaining personal goals while adhering to a character ethic aligned with timeless values and principles. Covey’s habits help individuals progress from dependence through independence, and finally on to interdependence, which he sees as the highest, most important level.

Covey writes: We live in an interdependent reality. Interdependence is essential for good leaders; good team players; a successful marriage or family life; in organizations. Interdependence is the attitude of “we”: we can co-operate; we can be a team; we can combine our talents.

It’s a concept all branches of the United States Military understand to their core.

But of course, success in the military requires its own particular set of skills and habits.

Crispin Burke, writing for Task and Purpose, has identified his six habits successful military commanders all have in common.

1. Stay in shape – mentally and physically

It was apparently Napoleon Bonaparte who said, “The first virtue in a soldier is endurance of fatigue; courage is only the second virtue.” Simply put, if you’re a slug, you won’t be able to fight very well.

The greatest commanders in history have always had the raw ability to sleep less, eat less, and drive harder than anyone else on the battlefield. The Duke of Wellington was supposedly able to stay 10 hours a day in the saddle on a single cup of tea, sleep just two hours a night, and limber up each morning by walking briskly for 30 minutes while swinging a riding crop.

Exercise has the dual benefit of increasing brain activity and reducing stress. Staying calm and focused in the midst of combat is a hallmark of great leaders.

2. Establish a battle rhythm — even off the battlefield

Time management becomes ever more crucial as rank increases, but you’ll never be able to manage your time if you don’t start doing it, from the very start.

Gen. Stanley McChrystal, who commanded U.S. forces in Afghanistan, cleared his head each morning with a vigorous seven-mile run while listening to audiobooks. McChrystal had to set aside time each morning before work to get his exercise in or he’d quickly find himself hopelessly mired by the work of the day.

It may be hard to find much time in your day that isn’t already spoken for by somebody else, but guard that time like a hawk, whether it’s for exercise, sleep, reading or reflection.

3. Grow your network

Covey wrote extensively about the value of interdependence because the truth is, individual talent will only get you so far. Whether you’re in uniform or jeans, you need to build a strong network to help you succeed.

Dwight Eisenhower spent nearly 16 years in obscurity as a major. Even worse, he almost ambushed his own career in the early 1920s when he wrote an article promoting tanks as the future of warfare — highly controversial at the time. But his mentor, Maj. Gen. Fox Conner, introduced Ike to another up-and-coming Army officer named George C. Marshall.

At the beginning of World War II, Marshall drained his own swamp, dumping nearly three-quarters of his division and corps commanders, and over 150 colonels. But he gave Eisenhower — just a full colonel at the beginning of the war — more and more responsibility until a few short years later, he was wearing five stars.

4. Get the ground truth

The higher up you climb, the harder it is to get the truth from the ground. You can’t always trust the reports from those lower down the ladder who may just be hoping to curry favor. Of course, you can’t be everywhere at once which is why many leaders find themselves a “directed telescope” — a trusted agent who will provide candid advice.

During his tenure as president of Texas A & M University, former Secretary of Defense Robert Gates set up an email account specifically for students to send him observations, complaints, and suggestions.

Of course, that other adage goes, don’t ask for the truth if you can’t handle it.

5. Never stop learning

There’s nearly 5,000 years of recorded military history. That’s a lot of lessons, and chances are, whatever you’re trying to tackle, someone else can help you overcome. Heck, what would we do without how-to YouTube videos?

And don’t be afraid to actually read. It exposes you to new ideas, helps improve your concentration and your writing skills (somewhat of a lost art).

6. Never lose your humility

With higher rank comes more privilege, or as Spiderman wisely said, “With great power comes great responsibility.”

On Christmas Day in 1998, Gen. Charles Krulak, then commandant of the Marine Corps, was visiting each Marine on duty at Quantico. Krulak was shocked to find Brigadier Gen. James Mattis as the officer on duty. Mattis had volunteered to serve Christmas duty to allow a married officer the day off with his family.

Leading through competence, character, and example will take you very far indeed.