Struggling with progressing ( League of legends )

Hello league players of steemit, i encoutered a problem in league of legends where i stopped progressing, and i'm not sure what to do, i learned how to farm better and read that you should not let enemy minions under your tower, because team's tower apparently is not your friend lol. And when i try to not let minions get close to tower, i get harassed a lot, which leads to me dying. So my question is how can i solve this problem?