3x 20-30 min interviews, over 3 days
Interview 1: discussed personal statement; Interview 2: close reading of unseen poem
Past papers; timed essays / essay plans
Find things that interest you and go really deep into them; have clear points to make about the texts you've read, and examples to back them up.
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.
Test taken:
Number of interviews: 3
Skype interview: No
Time between each interview: 1 day
Length of interviews: 20-30 minutes each
Of the two interviews in my college, one was largely personal-statement based, and the other was focused on close reading an unseen poem. For the close reading we were asked specifically to focus on line-by-line analysis, and the discussion later expanded into a broader conversation of some of the details discussed in the poem. For discussing texts in the personal statement, I would say one thing which I could have done to make preparation easier is to have a think about which aspects struck me in each one, and then focus in and try to remember a smaller detail which could be used as an example.
This goes for anything else you read as well, as we also discussed some texts I had read since writing my personal statement. Being precise with examples will also help with the larger conceptual questions they might throw at you, as I definitely ended up floundering with some of these. However, the atmosphere was a lot less intimidating than I was expecting, and the interviewers were really encouraging and tried to prompt me or give me time when I was struggling, rather than attacking what I was saying. It was mostly fairly easy to relax into the discussion.
I took past papers and wrote timed essay plans and essays.
I re-read my personal statement texts, and tried to make sure I was reading lots in general in the run-up to interviews.
Having a clear point to make about the texts is good, but they were also constantly trying to stretch these ideas, so again the best way I could probably have improved would have been to have more detailed examples from the texts I had read, in order to add more depth to the points being made without straying into vague concepts.