Soo i am a LoL player and well quite high rank if u ask me , diamond 1 . Soo some tips that helped me during my seasons :
A) Farming
You should focus on farming , Try to Last-hit all the minions.
B) Tilt-proof
You should always mute toxic players and YES! Report them.
C) DODGE GAMES
When u see weird stuff like Teemo support Mundo ADC , u should just dodge the game that will cost u 3 lp instead of a 15+min game and more LP.