The following verse from Guru Gita very beautifully summarizes the sadhana for a devotee:
Dhyānamūlaṁ gurormūtiḥ
pūjāmūlaṁ guroḥ padam
Mantramūlaṁ gurorvākyaṁ
mokṣamūlaṁ guroḥ kṛpā
Meaning:
Root of Meditation is Guru's Form.
Root of Worship is Guru's Feet.
Root of Mantram is Guru's Teachings.
Root of Liberation is Guru's Grace.
