George's development is going to be throughout the novel because he is one of the primary characters in Steinbeck's work. If you are looking for specific areas where his character is enhanced and "fleshed out" in great detail, pay attention to George's conversation with Slim helps to form much of chapter 3. The discussion between the two men is one of the first significant moments where George talks about himself and how he feels responsible for Lennie as well as his own background. Pay also close attention to how Steinbeck describes Slim as a priest in this setting. This helps to emphasize how George really does not open to anyone and when he does it is a moment where much is revealed. George is shown to be a character that balances the demands of real world, and its propensity to deny dreams, with his own visions of dreams that allow a transformative vision of reality to present itself. It is here where George is further developed in that he really wishes to embrace the world of dreams, but is constantly undercut by the demands of a real world condition that forces him to look out for others and put his own aspirations on hold.