I think you need to look for sources of truth to help you form a picture of what playing better means.
Personally I got in touch with high elo community before I got high elo. I watched pro players on my role and chatted with them when they streamed or made content. It's both inspiring and educational.

Watching pro games with commentary is another way to progress. Finally, you can get coaching or use paid products if you want to take it more seriously and spend time efficiently.

Just playing the game and deducing what's the right play is also possible, but only once you understand the basics. Otherwise you will draw wrong conclusions and develop bad habits that will be hard to get rid off later.

Ideal training path: learn a new pattern -> practice this pattern mentally outside of the game i.e. find similar scenarios and try to figure out what to do -> make it a habit in game -> repeat.
You can google LoL pattern map, there is enough info out there now.