4 Attributes the Best Leaders Constantly Hone The capacity to inspire others to achieve more is what defines leadership.

The table stakes of good leadership are pretty straightforward.

Good leaders have to be strong communicators; have a clear vision; be powerful persuaders; have solid business instincts; possess unflinching character and integrity; maintain a critical understanding of the competitive marketplace; be a strategic thinker; have expert decision-making abilities as well as a dozen other various traits.

However, there are at least four attributes that truly great leaders seem to continually strive toward.

1. Finding out what they don't know.

The only two certainties in business are change and uncertainty.

To improve their adaptability to those twin realities, the best executives, entrepreneurs and CEOs I've personally worked with all strove to enhance their understanding, knowledge and thinking.

Despite relentless demands on their time and attention, they each made learning and their personal development priorities.

Whether through mastermind groups, executive degree programs, professional coaching sessions or boundary spanning via voracious reading -- they all sought to know more than they knew.

Related: You'll Never Hear Successful People Say These 15 Phrases

2. Determining if they're wrong.

If you've worked for any stretch of time, you've known a boss or leader who knew it all.

Paternalistic individuals who squelched debate and discussion because they knew best---in other words, they believe they're never wrong.

However, anyone who thinks they're never wrong is often wrong in that thinking - that might be tweetable.

The best leaders understand that there's no monopoly on ideas or great thinking. The best leaders know that teams make better decisions than any individual.

Great leaders I've worked with all sought to pressure test their thinking, solutions and ideas through the gauntlet of discourse with their teams. In hindsight, the outcomes, results and decisions we collectively made were better than the mapped trajectories of any single input.

Related: 10 Behaviors of Smart People

3. Empowering their people to be the hero.

Piggybacking off that last point, great leaders know they can't do it alone. They don't try to be the hero.

I'm exposing my "inner nerd," but the most effective leaders don't strive to be Luke Skywalker -- they strive to be Yoda, who then empowers their subordinates to be the hero or young Skywalker.

My wife was a middle school French teacher before she decided to stay home and watch our children, but she had a teaching philosophy that embodied this leadership ideal, "It's better to be a guide on the side, rather than a sage on the stage" -- that might be tweetable as well.

Related: 5 Ways to Empower Your Employees

4. Valuing their people.

Lastly, great leaders strive to increase, reinforce and convey the value of their people.

Your organization will never reach its potential without a competent, engaged, highly-skilled and valued employee base. Your company's intellectual property, customer base, exclusive contracts or balance sheet will simply not last in the hands of an incompetent, disengaged, unskilled and under-valued workforce.

Each of these attributes are unlike other leadership traits in that they're each intangible, ongoing processes rather than a clearly defined "hard skill." However, what unifies these messy characteristics is that each is focused on others rather than the individual leader, and while having a focus on others is not a traditional "hard skill" it is a skill that's hard to find in many leaders.