The web dictionary defines self-mastery as “the conscious control of one’s behavior; self-command.” Personally, I like to think of self-mastery as the ability to maintain an objective perspective in a subjective reality.
In other words, self-mastery involves allowing your external environment to exist without judgment from the ego. From a higher perspective, reality is completely objective in nature, and does not involve the aspects of duality.
Subjectivity comes into play when the ego takes charge of the mind and defines reality according to the superficial filters that have been constructed throughout the duration of an incarnated being’s lifetime.
To put things simply, whenever you find yourself judging your environment, you are functioning from a subjective perspective. Of course, this mindset is not bad or wrong, it simply needs to be disciplined in order to maintain balance in everyday life.
For example, it would be rather pointless to view a painting if all that you were able to perceive was paint on canvas. Adding subjective meaning, an emotional response, is what makes you human, and defines your experience of life in third dimensional reality.
Meditation is an exercise that helps train the mind & body to relax and remain centered at all times. Even while performing mundane tasks, such as washing the dishes or doing the laundry, a meditative state can be achieved, which improves focus and proficiency.
While some may claim that true self-mastery is impossible, it is useful to remember that in truth, reality is objective is nature, therefore you are always in a state of perfection. It is only when you forget this truth that you make the mistake of thinking otherwise.