The reading
A tutor sets a question that specialists still disagree about, with the reading to go with it.
The tutorial is the oldest and strangest thing about an Oxford education. A student is set a question with no settled answer, reads for it, writes what they think, and then reads that aloud to a specialist whose job for the next hour is to test it.
Every claim has to carry its reasons, every objection has to be met on its merits, and vagueness is noticed immediately. Students used to being the quickest in the room find it unfamiliar at first, and most of them come to prefer it.

One academic · one or two students
Each student takes a major subject and a minor, both taught in tutorials by an Oxford academic. The major carries the greater share of the hours.
Every student writes one extended paper in their major subject, on a question narrow enough to answer properly in the time available.
Five afternoon labs, taken by every student, on questions specialists have not settled. The task is to reach a conclusion, not to summarise the reading.
The parts of the programme that can only happen here. Students put their arguments to an audience in the rooms where arguments are made professionally.
World-class guest lecturers. Each sets out a live problem in their field, then takes questions from the room. Students read on it beforehand.
The tutors do not push you to memorise the material. They work on your understanding of it.