How to improve in League of Legends

As we all know, everyone wants to imrpove on league, climb up to challenger. But I see so many people being salty in game, causing leavers, afkers, trollers to appear in ranked games. To be honest, to improve in a game is just playing over time with the proper mindset. There are just way too much saltiness in the game for people to properly enjoy it. I offer my own philosophy for League.

You have the right to complain about your teammates that feeds, trolls, afk and causes you a loss. At the same time, you do not have the right to complain about your teammates for not carrying yourselves to victory. The more you look upon your own mistakes instead of others, you start to improve.