How to get off tilt. Stop getting baited by your team. FOCUS on being as selfish as possible. Another guy said it best, find what puts you on tilt, and try to minimize/eliminate it. What always sets me on tilt, is being a team player. I know, right? When Im blowing summoners trying to help my support survive, when I'm trying to save my adc, when I'm listening to pings and crybabies who need my help jungling, when I throw a won lane trying to help a jungler who doesn't know when or how to gank, etc. Playing team oriented champions with team oriented builds, etc. You name it.
What sets me on tilt, is when I do those things, and get punished for it. So I blow my heal/summoners saving that yolo support who just can't help but go too ham, and then when I NEED those summoners to save myself from getting dove, or whatever, I dont have them and I rage. When I'm winning a lane, and the jungler comes and suicides, which sucks bad enough, but I die attempting to help him when I know it was a bad idea.
So the thing that eliminates this, is to start being as selfish as I possibly can. Don't waste summoners helping some idiot who is baiting you to your doom. I imagine for a lot of people, the same thing sets you on tilt, and continues to set you on tilt.
Do I get angry sometimes when I make poor plays? Yes, but I get over that stuff easily. Its fixable. Maybe I need to ward more, maybe I need to hit tab more before I duel someone with a completed tri-force and mine is still just a phage/sheen.
But yea, nothing in this game sets me on tilt more than try-harding and trying to be an ultimate team player. Its much easier to come back from some other guy suiciding then trying to come back from some guy baiting you. I catch myself on this tilt occasionally, but its always surprising how far into it, multiple games, before I realize WHY I am so angry, and then I fix it, and win a lot of games. But I can't for the life of me realize why I continue to let it happen. I think its because I make so many positive plays, and get in the groove when I am being selfish, that I start trying to make LCS big plays with my new "good" teammates, and get baited into lots of poor decisions.
Because thats all solo Q is; poor decisions. Especially in low elo, where I reside. Its more about capitalizing on the 500 mistakes people make, then making amazing plays yourself. Its hard to understand that if I just keep my nose down, get my CS, get what kills come my way, I'll probably win the game.