2x 15 minute interviews (1x general, 1x subject specific)
General - personal statement, general questions (specific and abstract); Subject - submitted essays, personal statement, general questions
Understand personal statement references, rest, read up on interview experiences
Dress comfortably (and warmly in badly-heated colleges!)
Remember this advice isn't official. There is no guarantee it will reflect your experience because university applications can change between years. Check the official Cambridge and Oxford websites for more accurate information on this year's application format and the required tests.
Also, someone else's experience may not reflect your own. Most interviews are more like conversations than tests and like, any conversation, they are quite interactive.
I had two interviews: one before lunch and one after lunch. My first interview lasted around 15 minutes with one interviewer and another person in the background, and my second interview lasted around 20 minutes with two interviewers. So not very long!
My first interview was a general interview. The interviewer mainly focused on my personal statement and asked me to evaluate the texts which I had mentioned, and asked me some questions on topics I was interested in (e.g. educational inequality). I was also asked some abstract political and social questions.
My second interview was a subject interview. They asked me to summarise my submitted essays and asked whether I still agreed with what I had written. They generally asked me questions that required me to think critically but did not require a lot of subject knowledge, especially for social anthropology questions. They also asked some questions related to topics mentioned on my personal statement and also some more abstract questions.
Spending time to understand parts of the book I wrote about in my personal statement which I didn't understand. Having a bit of a rest before the interview. Watching some videos and reading about interview experiences. But take everything with a pinch of salt as HSPS interviews vary greatly.
Some colleges are not well heated so it should be important to wrap up warm! Also, wear clothes that you're comfortable in (not too casual, but you don't have to dress too formally if that makes you uncomfortable!)