There is always a nagging doubt if I am making any progress towards Krishna. In many places Srila Prabhupada states that just as a hungry man feels satiated after eating sumptuous food, similarly a person making spiritual progress will will feel spiritual satisfaction (BG 2.59).
Spiritual satisfaction is but a natural product of our practice and faith towards Krishna. Experiencing spiritual satisfaction will kick out other unnecessary material thoughts from our mind. This, therefore, can also be seen as a symptom of advancement - our diminishing material desires. One of the major if not the major material desire within the living entity is the desire to find fault. We find fault with the people and things of this world almost religiously like it is our duty but because if we do not, then the world will not see true justice. Therefore as a beacon of hope and shining light, I will take upon myself to find fault and dispel darkness from humanity. Although the fact remains that I have such rasa or taste to criticize, we feign it in the name of improving life conditions. Enhancing life conditions can mean improving the quality of a product or a character of a person or solving a community wide problem.
Fault finding is a habit that modern culture actively infuses right from kindergarten. It comes in different flavors such as critical thinking, trouble shooting, discrimination, diagnosis, character development or just plain fault finding. Please understand I am not against critical thinking or trouble shooting. The real issue is our active desire or taste to immediately point the mistakes of others or other things and expect credit or glory. This active desire or taste one derives from criticizing is a deep rooted material phenomenon One who is spiritually situated will find fault only to the point where his sharp words help the person. If the same words were to belittle or hurt a person's sentiment then what use is there criticizing? Therefore a truly spiritual minded person will find fault dependent on the relationship with the individual.
So, to sum up my thought, a person who is aspiring to become spiritual, one way to ascertain progress is to test if the desire to extract taste from criticizing others has diminished. The more we detest pleasure criticizing, the more we are spiritually progressing. To put it differently, if we are forced to find fault due to a circumstance but at the same time do it out of duty for other's benefit and not out of implicit pleasure, then we can ascertain our progress towards Krishna.