This is something that has always perplexed me - Typography.
I've often been advised to improve my typography in the various projects I've done over the years.

I'm aware of the basics, for instance different typographical elements on a page or website, such as headers, body text, and annotations all need to be tweaked for readability and visual appeal. I know that different elements need to have their own place in a hierarchy of prominence. I know that different type faces are suited to different roles, for instance some will be suited to headers, and others the body. I know that the body needs to have the appropriate width, leading, and tracking for it to be easily readable.

To me all of that seems to be common sense - not a thing that needs to be studied for years and years.
But there is supposedly a wealth of other techniques and tips on being a better typographer - not that I've ever found any, I mean what more can there be (that isn't essentially what I've already said but in more words)?

Why do I struggle so much?
I'll create something, and in my eyes it will be perfectly readable, but then a typography "connoisseur" will come along and tell me it's wrong, I don't mind, I'm just a little baffled.