Q: What are the obstacles which hinder Realisation of the Self?
B.: They are habits of mind (vasanas).

 
Q: What are the aids for Realisation?
B.: Introversion of mind is the one and only aid.

 
Q.: How can I achieve the same?
B.: By preventing the mind from straying out after thoughts, desires and imagined objects of sensory perception.

 
Q.: What are vasanas?
B.: Habits of thought, accumulated tendencies of mind, and intellectual proclivities.

 
Q.: How does one get rid of these hindrances?
B.: Seek the Self through meditation in this manner: trace every thought back to its point of origin, which is only the mind. Never allow thought to run on. If you do so, it will be unending. Take it back to its starting place: the mind’s essence of pure consciousness- again and again, and thought and thinker will both die of inaction eventually.
           The mind only exists by reason of thought. Stop thought and there is no mind. As each doubt or depressing thought arises, ask yourself, “Who is it that doubts? What is it that is depressed?” Go back constantly to the question, ‘Who or what is this thing called ‘I’? Where is the source of the mind?’ Tear everything out and go on discarding until there is nothing but the Source of all left. And then live always in That and only in it. There is no past or future, save in the mind. Only present exists. Yes, even the present is mere imagination. It IS. That is all. Ehyeh Asher Ehyeh. [I am That I am]