My sister, who is an art professor at UVIC says, you can tell good art by three things: 1) You linger a tiny bit longer than the average piece in front of you. 2) You return to that image a second time for a closer look. 3) If you look three times, it's good art.....to YOU. What is good art to one is not good art to another, but really, you are only worried about connecting with THE one who finds it good art, not at all the others who skim over it.