It is difficult to transcend one's environment. So much to overcome. Parental upbringing. Education. Country. Neighbourhood. Friends. Peer groups.
Its all very well saying know yourself, but what does that mean beyond rhetoric? Know the person that your life has shaped. Ultimately its nonsense. How can one separate oneself from ones self?
For me, the answer lies in diversity. Being widely educated and widely travelled means exposing yourself to a wide variety of influences. Embrace people who hold views different from yourself and consider that they my hold some truths too. Allow yourself to consider the remote possiblity that you may be wrong.