I don't think it's a private school thing, I think it's more of a class thing.
I remember speaking to family members, friends of my parents and some of their grown up kids, work colleagues of my parents, and adults I knew through hobbies as part of my research.
This in particular being hard to do if your parents and their friends don't have varied jobs (or any jobs) or if you don't have the kinds of hobbies that let you meet people.
Online research is much easier now but one of the big problems is knowing what jobs are out there and what they involve if you don't have any exposure to them.
Exactly this.
The other thing is to consider broad sectors eg. Legal, finance, civil service and look into roles within a sector that is of interest.
Good idea but I wouldn't have known where to start with any of those! And surely there are so many sectors it's difficult to cover all of them.
I know a problem for me was not having a clue what different industries were out there and thinking that you had to pick something highly specialised - so for example I was interested in art/graphics/IT and went along those lines and ended up in the region of "media" - but I had no concept that I could have gone into product design, UX design, for a whole plethora of companies - anything like that which is where I'm looking at now. I just assumed media/ design/etc was all TV and magazines and stuff like that.
DH wanted to work "in the games industry" but has ended up (in a games company) doing a kind of project management, which is something I never really knew existed and I didn't really understand what he did until lockdown.
Because I now have a better understanding that big companies break down all the jobs of running them into really specialised parts that all work together I can see careers almost from a completely different angle. You could do project management in the games industry or the automobile industry or charity work or any number of other things, it's like an entire different dimension that I didn't know existed as a teenager, and has got me thinking differently as an adult. Something I'm vaguely interested in but don't have the right skills to do as a job might still be a sector I could find fitting work in, for instance.
I don't know if that makes sense. But it makes me wish I'd done maths or stats or science or something - I was good at those, I just had no concept of what I could do with those subjects and pictured being a scientist in a white coat in a lab which probably isn't for me.