Learning the teachings of the Guru to the best of ones ability. Living ones life in accordance with the teachings of the Guru. These are 'normal' responses. However, the best form of Guru Bhakti would depend upon the Guru and the Gurubhakt. There are various schools of learning and Gurus in these have different ways of teaching.
Some Gurus expect blind obedience, yet others expect a questioning mind.
Each seeker goes to the Guru with the object of being guided from darkness to light. Guru Bhakti is not the ritual worship of the Guru. It is whatever enables one to absorb the Guru's teaching so successfully that, at the end, the seeker becomes enlightened enough to be one with the Guru. A true Guru will strive to break all barriers surrounding the seeker. This includes the barrier between the seeker and the Guru.