These are important verses for memorizing. The index to these verses was taken from the Bhakti-sastri Study Guide compiled by Atmatattva dasa as used by the Bhaktivedanta Academy in Mayapur.
This is the list of 108 of the most important slokas from the Bhagavad-gita As It Is (1972 Macmillan Edition) by His Divine Grace A.C.