Steinbeck's style is what made his novel, Of Mice and Men, as great as it is today.
The way he used dialogue from the time period and his ingenious use of imagery really set the tone of the book. Steinbeck used many subtle ways of making the story seem real.
Steinbeck's use of slang and regional jargon really brought the story to the 1930's. He used words such as, "stake" in reference to the money they earned, and "scram" which means to leave in a hurry. Steinbeck also wrote with an accent; he purposefully misspelled works so that the reader would actually hear the southern drawl. This was very affective in his writing; it gave the book a real cense of realism.
Another interesting thing that Steinbeck did was use light the represent the passage of time; for example, "The afternoon sun sliced in through the cracks of the barn walls and lay in bright lines on the hay.
That was great use of cense imagery.
Steinbeck used animals to represent evil, although it was very subtle. He used a snake in the very beginning of the book just before Lennie and George entered into the novel. Horses were used just after Lennie killed Curley's wife; "The horses stamped on the other side of the feeding racks and the halter chains clinked." This was subtle but very effective.
Steinbeck's style is very unique and definitely original. That is why it is such a great novel.