If I were to attribute one trait to successful individuals it would be self-awareness.
Being self-aware is both understanding and recognising yourself and your thoughts, actions, values, and behaviors.
Every inch of you, who you are, what you do, and why you do it.
To be self-aware is to understand your traits, strengths, weakness, flaws, limits... and knowing how to use them to get the most out of yourself.
Self-awareness can also come from reflecting on yourself in the situation you're in to make judgment calls. Do you feel tired today? Are you feeling mentally burnt out? Are you firing on all cylinders?
Having said this, there is a fine line between being self-aware and looking too deeply into certain feelings.
For example, if you always focus on and highlight every small feeling of fatigue - it becomes a self-fulfilling prophecy that you're always tired.
Self-awareness starts with the simple process of checking in on yourself.
The human body is incredibly well designed to send you signals about how you feel and pick up signs in the world around you - so use them!
Self-awareness also comes from experience. The only way to truly know your traits, strengths, weakness, flaws, and limits is by encountering situations where they're tested.
What sets you above from the rest, however, is whether or not you can use this knowledge to make yourself better, and get more out of life.
You're one of a kind, and it's your job to find your strengths and what makes you tick, and exploit that uniqueness!