Best way to improve in LOL?

I haven't played League in several weeks lol, but when I was trying to get better I would usually just watch guides or youtubers. Even now that I don't play the game, I watch this youtuber named Neace. He does a lot of coaching and has some guides, even if you don't want to learn the champions he's playing, he's the self acclaimed King of Macro play, and it had definitely helped me.