If you tilt or flame easily try listening to some music!

Listening to some suuuper chill edm or hip hop helps set the mood for me when I play league. I've noticed I don't get tilted as easily if I'm listening to some nice, flowing, rhythmic beats. If you like music - and honestly who doesn't - then try listening to some while playing; it'll help you keep calm. Find some music that works for you, because in my experience it's one of the easiest ways to avoid getting tilted.

(If anyone isn't sure about where to start, then I recommend Unluck by James Blake. Exquisite production with subtle vocals that won't distract you.)