Great leadership can be a difficult thing to pin down and understand. You know a great leader when you’re working for one, but even they can have a hard time articulating what it is that makes their leadership so effective.

It was recently rumored that Starbucks’ CEO Howard Schultz would run for president, but Schultz shut the idea down almost immediately. He wrote in an article:

“Despite the encouragement of others, I have no intention of entering the presidential fray. I’m not done serving at Starbucks.”

Schultz commitment to his company over the temptation of the limelight is interesting. What’s admirable is his desire to be a leader who serves.

Service isn’t just something Schulz gives lip service to in the press; his mission is to create a company where people are treated with respect and dignity, and he backs this rhetoric up with his money and time. Starbucks will spend $250 million over the next 10 years to put benefit-eligible employees through college, and Schultz wakes up every day at 4:00 a.m. to send motivational e-mails to his employees (the email he wrote yesterday asking employees to show empathy for customers who have been affected by the plummeting stock market is an interesting, recent example of this).

It’s through a leader’s actions—what he or she does and says on a daily basis—that the essence of great leadership becomes apparent.

Behavior can change, and leaders who work to improve their skills get results.

In Schultz’s case, he’s been honing his leadership craft for three decades through, among other things, the direct coaching and mentoring of leadership expert Warren Bennis at USC.

Not everyone can take on Warren Bennis as a mentor, of course, but when it comes down to it, improving your leadership skills is within your control. You just need to study what great leaders do and to incorporate these behaviors into your repertoire.

There are six critical things that great leaders do that really stand out. Any of us can do the same.

They’re kind without being weak

One of the toughest things for leaders to master is kindness. Kindness shares credit and offers enthusiastic praise for others’ work. It’s a balancing act, between being genuinely kind and not looking weak. The key to finding that balance is to recognize that truekindness is inherently strong—it’s direct and straightforward. Telling people the difficult truth they need to hear is much kinder than protecting them (or yourself) from a difficult conversation. This is weak.

True kindness also doesn’t come with expectations. Kindness is weak when you use it in a self-serving manner. Self-serving kindness is thin—people can see right through it when a kind leader has an agenda. Think of Schultz, who dedicated $250 million to employee education with no strings attached, and as soon as employees finish their degree, they are free to walk out the door. That’s true kindness.

 They’re strong without being harsh

Strength is an important quality in a leader. People will wait to see if a leader is strong before they decide to follow his or her lead or not. People need courage in their leaders. They need someone who can make difficult decisions and watch over the good of the group. They need a leader who will stay the course when things get tough. People are far more likely to show strength themselves when their leader does the same.

A lot of leaders mistake domineering, controlling, and otherwise harsh behavior for strength. They think that taking control and pushing people around will somehow inspire a loyal following. Strength isn’t something you can force on people; it’s something you earn by demonstrating it time and again in the face of adversity. Only then will people trust that they should follow you.

They’re confident, without being cocky

We gravitate to confident leaders because confidence is contagious, and it helps us to believe that there are great things in store. The trick, as a leader, is to make certain your confidence doesn’t slip into arrogance and cockiness. Confidence is about passion and belief in your ability to make things happen, but when your confidence loses touch with reality, you begin to think you can do things you can’t and have done things you haven’t. Suddenly it’s all about you. This arrogance makes you lose credibility.

Great, confident leaders are still humble. They don’t allow their accomplishments and position of authority to make them feel that they’re better than anyone else. As such, they don’t hesitate to jump in and do the dirty work when needed, and they don’t ask their followers to do anything they aren’t willing to do themselves.

They stay positive, but remain realistic

Another major challenge that leaders face is finding the balance between keeping things positive and still being realistic. Think of a sailboat with three people aboard: a pessimist, an optimist, and a great leader. Everything is going smoothly until the wind suddenly sours. The pessimist throws his hands up and complaints about the wind; the optimist sits back, saying that things will improve; but the great leaders says, “We can do this!” and he adjusts the sails and keeps the ship moving forward. The right combination of positivity and realism is what keeps things moving forward.

They’re role models, not preachers

Great leaders inspire trust and admiration through their actions, not just their words. Many leaders say that integrity is important to them, but great leaders walk their talk by demonstrating integrity every day. Harping on people all day long about the behavior you want to see has a tiny fraction of the impact you achieve by demonstrating that behavior yourself.

They’re willing to take a bullet for their people

The best leaders will do anything for their teams, and they have their people’s backs no matter what. They don’t try to shift blame, and they don’t avoid shame when they fail. They’re never afraid to say, “The buck stops here,” and they earn people’s trust by backing them up. Great leaders also make it clear that they welcome challenges, criticism, and viewpoints other than their own. They know that an environment where people are afraid to speak up, offer insights, and ask good questions is destined for failure.

 Bringing It All Together

Great leadership is dynamic; it melds a variety of unique skills into an integrated whole. Incorporate the behaviors above into your repertoire, and you’ll see immediate improvement in your leadership skills.