For Roman history, start with SPQR: A History of Ancient Rome by Mary Beard; it is a useful first step into institutions, identity and historical interpretation.
For Greece, Greece in the Making, 1200-479 BC by Robin Osborne gives a stronger bridge from school history to university-style argument about evidence.
For visual and material culture, use Greek Art by John Boardman to practise moving from object description to interpretation.
The Complete Pompeii by Joanne Berry is especially useful for connecting domestic archaeology, urban space and site-based evidence to the kind of site or museum report the degree requires.
For Oxford-facing video material, the Faculty of Classics, University of Oxford channel is directly relevant to Classics faculty open-day and subject-exploration content.
For object-led preparation, combine The British Museum videos with the Ashmolean Museum channel, because both support close visual analysis and museum-based thinking.
For podcasts, The Ancients is useful for discovering topics that can later become deeper reading, while Ancient Greece Declassified can support broader ancient-world exploration through scholar-led conversations.
For structured online study, Greek and Roman Mythology treats myth as cultural evidence, while Rome: A Virtual Tour of the Ancient City links urban form, architecture and Roman social history.