Expertise in any domain involves the automation of basic skills, freeing attention for higher-level aspects of performance.
The biggest mistake you can make is believing you know everything. Stay humble and keep learning.
The merit of Marx is that he suddenly produces a qualitative change in the history of social thought. He interprets history, understands its dynamic, predicts the future, but in addition to predicting it, he expresses a revolutionary concept: the world must not only be interpreted, it must be transformed.