By practicing inner quietude, by stepping back from the immediate impulse to act, by asking the ego and desires not to make too much noise, and then turning towards the Divine with a will to receive the right indication one begins to feel a sort of gentle indication in the heart about the thing to be done.
Since this takes time, one should meanwhile act according to the highest light one can summon, generally the buddhi, and offer the action to the Divine with a prayer that may the action and will be attuned to the Divine Will and the results be such as the Divine Wisdom may determine and decide rather than what our ignorant mind wants and likes.
About Savitri | B1C3-04 The Growth of Divinity in Man (pp.25-26)