The state called consciousness is a subjective experience which we can contemplate. There are are different types of meditations. Never get angry with yourself for having thoughts or having difficulty letting go of the thoughts. Take deep breaths, using alternate nostril breathing to calm the mind. Observe your breaths, counting the breaths in a sequence of 1 to 4, then return to 1 and repeat the sequence, letting go of any thoughts you become aware of by simply returning your awareness to counting the breaths.
Purification is a necessary prerequisite to meditation.
By self-discipline, we mean giving up our dependencies and addictions, freeing ourselves from the demands of the senses and habits. It does not mean giving up material possessions or self-denial. Useless talking, reading bad literature, indulging in meaningless conversation, watching excessive TV, thinking about irrelevant matters, excessive eating, etc. are examples of behaviors to be curtailed. By self-study, we learn to observe ourselves and see how we are tossed about by our own thoughts and desires, and how we ordinarily react to external situations. We gradually learn to become less identified with thoughts, desires, and external forms, and realize our true nature which is behind our major life dramas.