This takes a lot of inner work, and requires a person to be very aware of themselves on a day to day basis. This means being conscious of any emotions that may surface, random thoughts that may come up, energy in the body such as tension, and most especially watch how you react to situations or people. It'll tell you a lot about yourself, your beliefs, and your subconscious mind. Often when we're children we'll develop certain patterns of thinking or ways of being and without realising, carry it into adulthood and beyond. Most of us are completely oblivious to our subconscious mind, and often end up blaming others for the way we feel or think... as if they're responsible for the way we react.
Creating a daily habit of practicing mindfulness and self awareness is a great way to begin shining the light into those 'dark' places within ourselves that we'd rather not go - but is crucial to understanding ourselves, breaking patterns, and moving forward to living consciously. Observe yourself often, and take time to question "why do I think this about myself/others?", "why did I just react in that way?", "how is my body feeling? what can I do to feel better?".
Self growth is imperative.