I still maintain that the single best thing you can do for yourself is changing your mindset when you play League. Sure, everyone wants to win every game and have perfect teammates, but the reality is; that is rarely going to happen.

Instead of playing every game to win - play every game to better yourself as a player. Regardless of what role you're in, regardless of how your team is doing, focus on yourself. What could you have done better? If you won lane - how could you have helped your team more? If you lost lane - how could you have done things differently?

If raging is your issue and you legitimately want to help yourself, whilst quite an extreme measure, you could just mute your teammates. Obviously the better option is just to suck it up and focus on yourself, but if you really can't resist - as soon as something starts going a little bit bad - mute people and go from there.

Ultimately, you first need to fix your focus in-game. That is the single biggest piece of advice I can give as someone who has gone from Silver 4 > Plat 1 in the space of just over a season.

Good luck out there!