Lord Chaitanya famously said that by speaking about Krishna to whomever you meet, you become guru. There is no need to move one's physical location. This is one qualification of guru- constant speaking about Krishna. To constantly speak about Krishna requires a significant quality - one of humility. The quality of humility cannot be over stressed, it is so important that it can tell the difference between a neophyte vaishnava and advanced. In Chaitanya Charitamrta Madhya Lila Ch 22 Text 131, Lord Chaitanya Mahaprabhu says one should associate with a devotee more advanced than oneself and who are endowed with a similar type of affection for the Lord. So we should seek the association of a vaishnava who is humble by nature and associate with him or her.
Below are the words of a pure saintly person stressing on the value of humility.
"One who is real guru never says, “I am guru.” He sees everyone according to jīvera ‘svarūpa’ haya kṛṣṇera ‘nityadāsa’— he sees their svarūpa, he sees that all are servants of Krishna. The guru has such a vision. His vision is not material vision, therefore he is guru. Through him we get bhagavān, Krishna. Guru says, tṛṇād api sunīcena — “I am lower than the straw in the street.” He is so humble. He has no pride in being a guru. But if someone says, “Don’t you know who I am? I am a great guru! Great ācārya!” This is dambha, pride. It is a demoniac characteristic, not a divine characteristic. It is not a characteristic of a vaiṣṇava-sādhu-guru. A real guru has humility. If one thinks, “I am guru.” Then he is not guru. He is goru, a quadruped, a cow or a bull."
- HH Gour Govinda Swami Maharaj