This may be moved to the discussion panel. It might be good for you to get a variety of ideas. I have two thoughts regarding his writing style:
1. Women feel under-represented. Of course this is about ranch hands from the 30s. However, Curley's wife does not even have a name. Every other reference to a woman is only about what she can do for a man. Curley's wife is painted like a lady of the night. The only other contact with women occurs when the men go to Suzy's Place for a drink and special "time" with women. The only other reference to a woman occurs because Lennie found a woman's dress to be soft and kept touching it until he got in trouble.
2. Steinbeck is very descriptive. From the opening scene by the pool to the bunkhouse to Crooks' room, I feel like the vivid imagery makes me understand the Depression a little better. When he describes places, I can see them in my head.
The link below will help you think about how Steinbeck write to better craft your own answer.