My interview was in the morning and, because I had a long train journey to get there, I came the previous night and stayed overnight. The college provided accommodation, dinner and breakfast free of charge. A student met me when I arrived, showed me to my room and gave me the information I needed. I had 2 interviews in one day. I can't remember how long. Both were with 2 biology fellows (two went on to be my first year supervisors). Both interviews were entirely subject-focussed. I also had a 1 hour college test but they no longer have this, since the introduction of standardised pre-interview test for all applicants to the university.

A few questions could have been straight off an A level paper. Others were more challenging, but didn't require any basic background beyond A level. The challenge was in how you applied the knowledge. Further reading was quite useful here since it gave me more material to draw on and helped me to think about questions in ways I might not have otherwise. Many of the questions were quite open-ended and several questions involved visual prompts (e.g. photos, graphs). In one interview I got asked a bit about some of the subject-related reading and experiences I'd mentioned in my statement.

I felt less nervous than I expected to - the interviewers weren't very intimidating and tried to put me at ease.

Reading. Browsing the popular science section of bookshops I picked out some books that looked interesting. Some of them proved to be absolutely fascinating. Because I had enjoyed them so much, they were easier to talk about in my personal statement/ interview and it was easier to draw on some of the ideas to answer the more challenging interview questions. Science news outlets provided an accessible way to learn about more current science (often a bit lacking from the school syllabus). Simply "liking" Facebook pages of various science outlets was a great way to find articles (e.g. BlueSci, Chemistry World, Kew Gardens, Natural History Museum, Guardian Science, Universities such as Cambridge, Durham, Bath). Podcasts were also a great way to learn new things. I liked the Naked Scientists (which is actually Cambridge-based) and for any budding Plant Scientists I can recommend In Defense of Plants (which also has a YouTube channel and blog).

I did have one mock interview at school but it was nothing like my real ones so a bit useless, really.

Also, just making sure I was familiar with all the A level content I'd covered up until the time of my interview.

One more thing: Cambridge runs an "HE+ Website" that has loads of useful resources and links for exploring your subject. I didn't know about it when I was applying but it's worth checking out. http://www.myheplus.com/

Whilst ability is important, so too is enthusiasm. Your interviewers will most likely become your teachers so they're looking for someone who is engaged and has a genuine interest in the subject - someone they'll actually enjoy teaching. Really think about why you want to study the subject, what do you love about it? If you're struggling, do some extra reading. I found my A-Level syllabus quite dry, but when I read around the subject, I discovered so much fascinating science and this helped fuel my enthusiasm.