I did an undergraduate double degree in law and finance, a...

I did an undergraduate double degree in law and finance, a masters in finance, and my professional background is in merchant banking, and to be honest a lot of what i learned through my educational & career background isn't particularly helpful when it comes to investing. Indeed, some of the stuff i have had to actively "un-learn" along the way (and am still actively "un-learning").

I reckon investing is a combination of year 8-9 math, university level accounting, and then just controlling emotions/being patient. The math component i learned while at uni and on the job, the majority of the accounting stuff i've learned along the way just by reading enough annual reports cover to cover to figure out how accountants tend to think about the world, and then controlling emotions is a constant work in progress and something i am actively working on.

Mistakes are fine, everyone makes them - i have an extensive list of personal favorites - and it's best to make them when your stakes are low / when you're starting out. The most important part of the exercise is some honest introspection if/when things go wrong, and try to make a mental note so you don't repeat the error. As you go along with time you'll figure out what works for you and what doesn't. Putting aside speculative stocks (stocks that don't earn money), my personal experience is that the easiest way to lose money is either to simply pay too much to begin with or invest in something you don't really understand, so it's helpful to have a shorthand framework for valuing businesses and don't touch things you don't understand.

As for reading, well, there's plenty out there. I'm sure there's lists of books floating around on the internet for the prospective value investor that are much more comprehensive than i could muster off the top of my head, so i'd just google that. But, i reckon more important than reading books is just sticking your nose in plenty of annual reports and just looking at lots of different companies.