In Chaitanya Caritamrta Lord Caitanya says that sadhu-sanga, the association of a great saintly person, is very important, because even if one is not advanced in knowledge, simply by association with a great saintly person one can immediately make considerable advancement in spiritual life.
The quest for spiritual advancement is disturbed when men and women come in contact, then the tendency is they become mutually attracted to each other and then the focus on spiritual advancement becomes distorted.
Lecture on ‘Don’t make Prabhupada disappear’ – 26th Oct 06 – Dubai
Prabhupada had such an ambitious plan to change the world, because harer nam harer nama harer nama eva kevalam: "Harinama is the only way for spiritual perfection in this age." But Prabhupada saw that people don't have time, nor the inclination. This modern society makes the people into demons. So this simple life is very conducive for spiritual advancement.
Lecture on "Living without Electricity" – Salem – 26th Nov'07
The more one makes spiritual advancement, one feels humble and as one's devotion is superficial that much he feels that he is a great devotee.
Advancement in Krishna Consciousness depends on attitude of the follower.
Spiritual advancement without mind control is simply an illusion.