No problem, I remember being in this position a year ago well and it's always great to talk to current applicants.
I did get an offer from Cambridge in the end but it was a long journey, probably best answered with the next question...
I applied for Medicine as a deferred applicant (because I am from Scotland and a year younger so I wasn't eligible to make a normal application). I originally applied to Newnham college and I was interviewed there. In January, I received my email from Newnham saying that they rejected me but did submit me to be considered in the Winter Pool (which is where another college can offer an applicant who was rejected by the college which interviewed them if they have space. This is also to try an ensure that the best applicants get an offer from the university across the gathered field even if they have to be shuffled across colleges). I was not offered a place by any college from the Winter Pool. I was, however, informed that I was eligible for consideration in the August Reconsideration Pool, which is a second chance for some widening considerations applicants to receive a place for a course if there are still spaces available after A Level results day, provided they meet the minimum entry requirements for their course. So this means that I needed to get minimum A*A*A to be considered for Medicine in the ARP. I ended up getting A*A*AA (I did four subjects) and applying almost on a whim and I definitely didn't expect anything from it. But I was offered a place by Fitzwillam college (so underrated high key I never hear anyone talk about it!) and I guess here I am.
Sorry for the ramble, but I guess I just wanted to highlight an unconventional journey to being accepted and like to trust the process because for six months I was a Cambridge reject so I know how that feels too and it's not the end of the world.
Anyways, for interview my tips would be probably what you've heard before, revise A Level content and go over anything scientific you mentioned in your PS in DETAIL and make sure you can explain in simple terms and break it down and elaborate on it.
Try and get as much practice as you can, I was really lucky as a lot of my teachers agreed to do "academic" type mocks and I was applying for Med so I had lots of general interview practice as well, but definitely get used to speaking about your subject out loud, whether that's to your friends, your Mum, your mirror, anywhere at all!
I think something else that is a bit wierd about the interview that I certainly didn't know was that it feels a bit time pressured. It definitely is a discussion and a back and forth, and as far as interviews generally go 20-25 minutes is not that short, but they just have so much to get through it feels a bit rushed. So, don't feel like you're slow or they don't appreciate your answers, they just have to get through as many questions as possible so you can have the best chance of answering well on all of them.
When I thought I was rejected a specific piece of feedback I got was to be "more concise" lol I can be quite verbose. So, I don't know if the time pressure is specific to the sciences or what, but I think a good general tip is to just follow baseline instructions. If they ask you to answer something in one sentence or one word, just keep it to that! It can feel wierd because common interview advice is also "say what you're thinking" and this is definitely good advice, like always be ready to give ideas, but not to the point where you are not following instructions - I think that is something that lowered my performance originally.
Hope everything I have said is helpful. Wishing you all the BEST of luck honestly and I am happy to help with anything at all you're not bothering me with questions, honestly. xx