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.
Number of interviews: 3
Skype interview: No
Length of interviews: 20 minutes each
The questions were very academic-focused. Each interview had a main setting/theme for me to tackle. It started with the introduction to the topic, some questions with specific / numeric answers, then generalized it / made it more complex. I tried my best to understand it and give my best shot.
Note that before one of the interviews the interviewer asked whether I had heard of the (retracted) question. I hadn't, so he proceeded to ask me, but I don't know what would happen if I said yes.
The atmosphere was a bit weird (it's an interview, after all) but I tried my best to blend into the atmosphere of the
Mostly, I prepared using the past papers on the official website. I mostly looked at questions online and relied on official sources the most. I was also lucky enough to have a
Practise thinking aloud on your own: try speaking your solution to questions out loud and writing it down legibly.
As for a piece of advice: ALWAYS THINK OUT LOUD!!!!!!!!!! It's cliche at this point but if you don't explain what you're doing the professors have no way to assess you. If you don't understand (or in rare cases, can't hear clearly) the question, ask again. Better to have a good grip of the situation than to tread down the wrong path.