They read to question, not to finish
Most aspirants treat a chapter as a task to complete. Toppers treat it as a problem to interrogate. Shubhra Ranjan, whose students have consistently placed in the top 100, has said in multiple interviews that the single habit separating serious candidates from successful ones is margin annotation, writing one question per paragraph, not a summary. The question forces active recall. The summary is just copying in your own handwriting.