Practicing yoga is that unfaltering effort to still all the fluctuations. This theme binds the thirteenth yoga sutra of Patanjali yoga.
tatra of these, under these circumstances, in that case
sthitau as regards steadiness, as regards perfect restraint
yatnah continuous effort
abhyasah practice
Practice is the unfaltering effort to still these fluctuations.
Practice is the effort to quieten the fluctuations in the consciousness and then to move towards silencing it - to accomplish a constant, balanced, tranquil state of mind.
In order to free the mind from fluctuations and vacillations and to reach a state of stability, the practician is advised to intensely practise all the yogic principles, from yama to dhyana. These encompass every discipline - moral, ethical, physical, mental, intellectual and spiritual.