Well, I'd start by looking at pictures by any of these folks:
Paul Cézanne
Edgar Degas
Édouard Manet (Le Bar aux Folies-Bergère is my favourite)
Claude Monet
Camille Pissarro
Pierre-Auguste Renoir
I also think it's important to understand how radical they were at the time. Of course, they appear very quaint now as prints in dentist waiting rooms, but understanding their role in shaping the modern art world will help you become interested in them.
