Steinbeck's prose style reminded me of that of Ernest Hemingway. Here are the opening sentences of "Of Mice and Men" for example.
A few miles south of Soledad, the Salinas River drops in close to the hillside bank and runs deep and green. The water is warm, too, for it has slipped twinkling over the yellow sands in the sunlight before reaching the narrow pool.
I wondered whether Steinbeck had been influenced by Hemingway, but then it occurred to me that both of them, as well as some of their contemporaries, had been influenced by Sherwood Anderson. I referred to Anderson's story "Hands," which is available as etext in eNotes, and found that same plain but at the same time rather poetic style in the prose. Steinbeck is probably more like Anderson than Hemingway because of his interest in ordinary Americans doing commonplace things.
Steinbeck's philosophy that men's joining together into a fraternity of purpose as a solution to their disenfranchisement is clearly evident after reading half of Of Mice and Men. (George's conversation with Slim in Chapter 2 is absolutely intrinsic to this theme.) And, the fact that Curley's wife is a mere genitive of Curley additionally demonstrates this theme of men's fraternity; she acts only as an Eve, a negative that pulls men from each other in another way besides the alienating circumstances in which they must live.
Regarding the structure of this novella, Steinbeck considered Of Mice and Men as a drama for the theatre. With each chapter as a scene and the beginning and ending chapters taking place in the peaceful clearing outside Soledad, Steinbeck ties his work together very neatly.
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.