So, specifically, how will your "proper audience" find your good photos? Who exactly are those people? What do they want to see?
If you are going to try and sell your work, you will sell more if you understand what your market wants.
As to how I judge my feedback is more artistic than numeric. If 4 in 10 people liked a photo I did, that would indicate a truly huge market; for example 4 of 10 American's liking my work would mean a market/following of over 100 million people. Truly unrealistic to think I could get there.
I do listen carefully to both positive and negative, I listen for clues as to the sincerity too. If its BS being thrown my way I want to know.