When we speak of the dust of the lotus feet of the Spiritual Master, we are speaking of humble approach to serve his instructions. Unless we humbly serve the instructions of the great soul, it is Krishna's arrangement the He never reveals Himself.
No amount of study of scriptures, austerity or charity can help us know God. The only way is to follow the footsteps of saintly people. When we have faith in that, that faith shows us the way.
In order to have simplicity of mind one must have simplicity of life style, which means one must be detached from gain or loss, pleasure or pain, honor or dishonor, happiness or distress. One must simply be seeking purification of consciousness.
A devotee seeing other devotees getting blessed, seeing other devotees being empowered, seeing other devotees joyful, that should be our happiness. That is a Vaishnava, that is the standard of Vaishnava.