Hammer every thought in your mind thinking of how to serve Krishna.
Keep your mind under captivity of remembering Lord Krishna.
You are where your mind is.
Unless one's mind is at least somewhat peaceful one cannot even begin to think about spiritual subjects.
Lecture on “Overcoming the IIT disadvantage” delivered at IIT Chennai on 19th Nov 2006
Mind is seat of senses, to control mind is very important aspect. We need to understand our duty to train our mind. We need to discriminate and we need to chastise the mind sometimes, we need to distinguish what is bhakti and maya.