Self realization, god realization, enlightenment liberation from cycle of birth and death all meant the same. When we realize our true nature, reach our soul atman existing in heart it is called self realization. As souls atmans were God Almighty in miniscule form and having the same essence, self realization is also called god realization.
When a person realizes self the journey of soul atman within comes to an end. This liberated soul atman finally enters abode of God (Vaikuntha in Hinduism). The liberated soul atman finally merges with God and hence self realization is also called God realization for we succeed reaching God forever. Realization of true inner self and God mean the same.
Indulging in spirituality as detailed in Bhagavad Gita human beings finally succeed reaching stage of enlightenment. Enlightenment is the stage when in absence of dross impurities within a soul atman reaches state of absolute purity. A pure soul atman need not manifest a body any further. The pure soul atman finally liberated self from cycle of birth and death forever.
The ultimate goal of human life is reaching God, realizing God. This is done indulging in spirituality never religion (path of rituals).
Negation of karma in totality is necessitated to reach state of absolute purity.
The steps to reach state of self realization include demolition of ego in totality, overpowering five senses and mind in stages. Furthermore practicing absolute celibacy human beings finally succeed full awakening of kundalini shakti, the coiled Serpentine energy lying dormant in base of spine. The moment kundalini reaches Ajna chakra, the cosmic journey of soul atman finally ends. One immediately becomes an enlightened one, a bodhi, a Jina… a Mahavira forever.