"The control of those vrttis occurs through practice, abhyasa and dispassion, vairagya." Swami Veda Bharati
Explanation: Because, as was specified in the second sutra, yoga is the cessation or mastery of the vrittis, the yogi seeks to do just that, and the means to do so are practice and dispassion. Practice means the practices that develop discrimination, which must be done with strong mental, moral and physical discipline to be effective, and dispassion means reducing attachments, i.e., lessening the thought that "this is mine." Swami Rama explained non-attachment as one would do when a guest in someone's house: everything is there for you to enjoy but not to take.