I had no idea what I wanted to do in school and went back and for between a lot of different options. I'm now studying something else entirely anyway! So some of the bits I've picked up over the years....
Employment Prospects - A Red Herring?The thing I would advise is firstly, although it does seem like a big factor, don't focus overly much on employment prospects - as research has shown, the employment trajectories of STEM and non-STEM grads in the UK is equivalent:
https://figshare.le.ac.uk/articles/report/The_employment_trajectories_of_Science_Technology_Engineering_and_Mathematics_graduates/10234421 Bear in mind too that most graduates end up doing a job unrelated to their degree anyway. Additionally, "graduate income" averages can be wildly skewed by a handful of graduates going into very lucrative jobs while the majority end up going into much more "rank and file" type roles. Just considering how many grads are going into jobs, and how many of those are going into professional level roles, is probably more useful information (albeit not always applicable - what is deemed a "professional level role" in a certain field may not be practical to go into from an undergraduate degree e.g. in the heritage/arts sector you're unlikely to go directly into one of those roles and would probably need to work a couple years in a slightly lower level role and/or get a masters. But if that's what you want to do, that's not necessarily a problem!).
Most generalist grad schemes don't care at all what subject you studied at degree level, and also don't generally care that much where you did your degree. Unless you have a specific career in mind (e.g. healthcare professions, engineering, etc) which is due to your interest in the
career and not the supposed earnings potential of it, focus on picking something of
intellectual interest to you. As realistically otherwise you're most likely to end up in some kind of generalist grad scheme like role which is effectively an office job where you're going to spend 8 hours a day trawling through excel and sitting in meetings. You may as well do a degree which is genuinely interesting and enjoyable to you, than one that just has you do much the same thing for three years before you're even getting paid!
Of course for some jobs you do need a specific degree (usually with specific accreditation). This is normally in professional/public services roles e.g. healthcare professions, teaching, social work, professional psychologist roles and to a lesser degree things like engineering, computing/"tech", and law (you can go into those with other degrees potentially). The former categories usually require some work experience as part of the application; the latter ones usually don't. It's usually worthwhile to explore the profession anyway to the extent you can to understand what it is or isn't (engineering is an office job for example, mostly!). If you know you want to pursue one of those areas, make sure you're looking at appropriately accredited degrees. And remember for the former categories, where you study tends to not be important at all.
In fact the only roles where the uni you studied at really make a significant difference (in your favour or not) are investment banking or management consulting. Both practically require you to go to a uni they consider a target uni to have a good shot at getting in (both are also extremely competitive), but any subject is fine for them.
Interests, aptitudes, strengths and weaknessesIn terms of your interest for the degree, do make a point of
confirming your interest in the course by actually trying out the material for yourself beforehand. So read around your subject- actually read around it, not just skim through TSR and wikipedia pages, look at actual texts from the subject, try your hand at the problems or thinking about the analysis of the materials you've read etc. If you think you can do that a lot more (and especially if you'd like to) that's a good sign! If you find it getting boring fast, that can be a red flag. You won't necessarily find it all immediately accessible of course, but that's normal - the important thing is if you can find yourself wanting to push more into it and learn more about it. If you don't have that motivation, it can be hard to force yourself through an entire degree in something.
Also think about your strengths and focus on following those and your interests, rather than being taken in by notions of what a degree may or may not lead to in the long run (since as above, it basically all evens out anyway within ~10 years of graduating). If what you're best at really is writing essays, then do look at courses where that is a major part of the course, so you can play to your strengths! If you spend all your free time reading about coral, plankton and benthic food chains, do consider a degree in (marine) biology! Consider your weaknesses too; if you absolutely hate maths and it makes you cry and you can't stand the thought of doing it, stop trying to convince yourself to do a degree in economics/CS (I see this all the time on here and it's truly maddening...).
Subject matters and league table rankings Additionally make sure you understand what the degree is and what it isn't. For example, maths degrees are very different to the kind of maths you do in A-level, and if you aren't aware of that it can be not at all what you were expecting or wanting to do! In a similar vein, a lot of people do chemical engineering because they think it's a degree in applied chemistry - then are dismayed to find that chemistry is a very small part of that degree. Likewise a CS degree is not a degree in programming - it's a degree in computer science and programming is a means to an end (and often quite a small part of the course at a number of the "top" universities for it, whatever such notions are worth). For a non-STEM example, also consider that a degree in English lit is a not a degree in "reading", and just because you enjoy reading for leisure doesn't necessarily mean it's a good fit - it's a degree in literary criticism and analysis. If you don't actually like that part of reading literature, then you probably wouldn't enjoy the course.
Finally don't get
too hung up on league table rankings. They can be useful in specific contexts but too many students use them without much critical thought and rule out perfectly good universities (including ones they themselves prefer!) because this year they're slightly lower than they were last year or something. Year on year placement in league table rankings and vary enormously for most universities, and the metrics used by them are very varied and not always indicative of what might be important to
you in a course. Also bear in mind "general" rankings are basically meaningless - you really need to consider them on a subject specific level. It might be great if Cambridge is number 1 uni this year, but if they don't teach your subject that's irrelevant to you!