To get good you need three things: 

- learn the fundamentals 
[composition, balance, unity, white space, contrast, etc]

- practice, practice, and practice [create studies around typography and images practicing various forms of the fundamentals]

- study from life, visit museums [design is everywhere, seek the fundamentals in everything]

how did you learn the fundamentals? i think i'm struggling to learn in a real way, i see random things here and there but no clear "curriculum"

Self practice
Then art school (the cheat code at least when I went. Idt it’s relevant now unless you study fine art)
Then more self study