Advice for A Levels & Preparing for Oxbridge Applications

How to stand out in your subject and the relative values of different parts of the application will differ depending on your subject. For example, work experience is not common in Maths but is much more relevant to Medicine. Which subject(s) are you considering?

I’m leaning more towards Maths and Finance, so for now, I’ve chosen Maths, Economics, Computer Science, and Further Maths as my A Level subjects.

i applied to maths and got an offer from oxford today, so I can tell you what worked for me. For context i took maths, fm, physics and cs and was predicted 4A*
I went to quite a few summer schools, including a physics summer school which I linked back to maths. I was able to write about specific things I learned there and link them to follow up activities e.g. taught a lesson on it. I also mentioned a problem I saw in a maths book i read and highlighted why that problem interested me (did not describe it just mentioned it by name). I mentioned competitions: tom rocks maths essay competition and ritangle, briefly touched on maths challenge (never got olympiad so didn’t linger too long). Mentioned a hobby I had and linked it to logic and maths. My intro was about how I see maths and why I enjoy it, not too generic and quite brief as they don’t care that much about the wishy washy stuff.
Generally I gave specific examples of where I showed passion and things I went on to learn as a result
The balance was tricky- you might have to find what works for *you*. What I did was lock in completely for a few weeks to do well in my mocks, and outside of that time i was focusing on supercurricular activities. Keep in mind you can get a huge amount of uni stuff done in summer so if you need more time for mocks then take it as your predicteds should be as good as you can get them.
For maths admission tests: past papers. Started in sept, exams in late oct. For interview questions you can find practise ones on the internet. I used the TBO booklet. If you just learn random stuff it might help you- i’d seen the concept of one of the questions i got given at interview before in a youtube video.
I was not interested in finance but try to find a placement over the summer if you haven’t already! I have heard experience will go a long way.
Any other questions feel free to ask

1. a lot of interesting problems i found by watching youtube videos- 3Blue1Brown, numberphile and similar. I found a few by reading a book (yes only one 💀) but also summer schools helped me out a lot. Often the hard part is to find things to work on, but if something interests you then look more into it.
2. I attended the Senior Physics challenge ran by Isaac Physics, which was great from a maths standpoint as I used a lot of maths there. It was quite intense though and I don’t remember much of what i did now 😭. If you’re a girl, you should check out Murray edwards STEP summer school and st. john’s women in maths summer school. The st. John’s one was amazing, I can’t recommend it enough. You could also check out UNIQ and sutton trust.
3. I’m pretty happy with everything I did. One thing I will say is I wasted a lot of time on my phone when I could’ve been using that time to do my hobbies that I temporarily gave up when things got busy. I also wish I had more confidence in myself and my ability as I think my lack of this caused me to perform worse on entrance exams.

Sometimes I would not understand things right away and that would panic me as you say, but consolidation always fixed that. Definitely had and have the fear that maths will get too hard for me, especially further maths, but it never did, so just believe in yourself!
I originally wanted to study Computer science, and then cs/maths. I did a physics course in year 12 (COMPOS) and loved that so much I was considering Physics/maths joint course. I then sort of realised that my interest in physics and computing kind of stemmed from my love of maths, so doing anything but pure maths wasn’t truly what I wanted.
I took ages to decide between oxford and cambridge, but in the end I just chose the one that felt right which is probably not a very useful answer lmao.
hope that helps

Just to note for OP, whilst I'm not personally familiar with the summer programmes that this user has mentioned, I'm assuming that these are the free / very heavily subsidised access ones run by the university. These ones are definitely an asset to an application and are likely very worthwhile, should you meet the access criteria.
However, many private companies also offer summer programmes that are not affiliated with the university and are run purely for profit. These are not likely to be worth their time and money and, despite their advertising, are not much benefit to an application compared to the time and effort they require.