Bhakti is the path of devotion; and it is the motor that drives our seva. It means turning the entire mind towards Brahman in deepest humility and love; to melt in the fire of that love, so that whatever we do, we do for Him. He is the true object of our service. In Bhakti there is a clear dualistic approach to God: here I am, small, flawed and powerless. You are my being, You are my saviour, You are all-love, all-power, all-healing. I give myself to You; I give myself entirely.
In most cases, Brahman is loved and worshipped under a specific name and form. This is the reason there are so many deities in Hinduism: since we are all different, it is only reasonable that we should love God under whichever name and form we are most drawn to. God can be a Father or a Mother; he can be a child or a friend. He can be one of the great avatars, Krishna or Rama, or a god with an elephant’s head (Ganesh), or we may align ourselves with Hanuman, the monkey god and Rama’s greatest devotee. He can be the great Destroyer, Siva; or Siva’s consort, Saraswati. Or he can take the form of a Guru, a human being who has in him or herself already attained oneness with Brahman, and thus can guide us there. The main thing is the flow of devotion, for it is that flow that sweeps away the detritus of selfhood that separates the loved from the beloved.