I don’t think she got good advice or support from her school. I think she said in a video that her school didn’t typically send a lot of people to Oxbridge (which makes sense, given the kind of school and where it is) so I don’t think she got the kind of intensive Oxbridge interview support and coaching that students at other schools tend to get. I also think that she was (and still is) fixated on the ‘more is better’ approach and she genuinely thought that if she did loads and loads of random prep she’d be ok. What she really needed was some training in thinking on her feet, as I bet getting questions she hadn’t specifically prepared for really threw her.
Hi I've not posted on here before but just wanted to add to this point
I'm a student at Cambridge so have a pretty good idea of the whole Oxbridge process, and went to a school that sent basically no one to Oxbridge so did not get any useful support there really. HOWEVER, everything you need to apply to Oxbridge is widely available on the uni websites, so many example interviews are available on youtube, there are practice admissions tests and outreach programs where Oxbridge students answer questions from applicants so there really is no reason Ruby couldn't have prepared better, although I suspect she would have struggled with the main purpose of the interview which is to give you information you don't know/have never seen before and see how you deal with it.
Also, the admissions officers really are looking for a genuine enthusiasm for your subject, my tutor has told me they can sniff out someone who is only applying because of the Oxbridge name (or *aesthetic*) straight away and they will not be getting an offer unless they are incredibly impressive.
Oh and a final point, obviously Ruby has done very well with school and grades, but my experience of the people at Cambridge has been that you shouldn't have had to work THAT hard to get the grades that you needed at A Level (for STEM A*A*A, for humanities A*AA). In general, everyone did put in the work at school and has a good work ethic, but most people also have a very full social life and had several hobbies that they put a significant amount of time into or part time jobs, and they balanced these perfectly happily throughout sixth form. Ruby was doing 14 hour study days and basically only focussing on studying throughout A Levels, or at least that's what her videos suggest, and got A*AA. Obviously those are really great grades, but Oxbridge cram 10-12 weeks worth of content into 8 weeks so I think she would have struggled to deal with the intense workload of an Oxbridge degree if she continued to work in her current mindset of more hours = more productivity. Especially because she seems to give herself extra work to do by writing and rewriting to do lists and notes.