Sutras 12-16

1.12 abhyasa-vairagyabhyam tan-nirodhah

abhyasa - personal application/practice
vairagyabhyam - non-attachment
tad - (of) those
nirodhah - cessation; dissolution; restraint; suppression; control

Both practice and non reaction are required to still the patterning of consciousness.
Consciousness is elevated by Abhyasa (Devoted Practice) and Vairagya (Remembering the Self).

1.13 tatra sthitau yatno'bhyasah
tatra - of these; there (here: between those two practice and dispassion)
sthitau - stilling; coming to rest of the mind-field
yatnah - endeavor; effort; exertion
abhyasa - (persistence) personal application/practice

Practice is the sustained effort to rest in stillness.
Devoted Practice, Abhyasa, cultivates the unfolding of consciousness. 

1.14 sa tu dirgha-kala-nairantarya-satkarasevito drdha-bhumih
sah - that; this (practice)
tu - however; but; moreover
dirgha-long; (for) a
kala - time; long time
nairantarya - without interval
satkara - reverence; devotion
a-sevitah - pursued; practiced
drdha - established; firm
bhumih - ground; plan

This practice becomes firmly rooted when it is cultivated skillfully and continuously for a long time.
Abhyasa is nurtured by a sustained, steady rhythm and a dedicated heart. 

1.15 drstanusravika-visaya-vitrsnasya vasikara-samjna vairagyam
drsta - seen/perceived/experienced
anusravika - heard of, revealed
visaya - matters of enjoyment or experience
vitrsnasya - one who has lost craving/thirst (for) 
vasikara - mastery; powers
samjna - full knowledge; consciousness 
vairagyam - dispassion; detachment; non-attachment

As for non reaction, one can recognize that it has been fully achieved when no attachment arises in regard to anything at all, whether perceived directly or learned.
With constant Remembrance of the Self, Viairagya, all yearnings fade.

1.16 tat param purusa-khyater guna-vaitrsnyam
tat - that
param - transcendent; ultimate; supreme
purusa - the conscious Being; the Witness
khyateh - [due to] realization of purusa
guna - the attributes of matter (prakrti): sattva, rajas, tamas, primary-consituents of Nature
vaitrsnyam - state of being free from all craving

When the ultimate level of non-reaction has been reached, pure awareness can clearly see itself as independent from the fundamental qualities of nature.
When consciousness unites, it remains clear and unaffected by the external changes of nature, the gunas. This is the ultimate Vairagya.