Don't be toxic
Remember people, Teemo had a job at Pizza Hut once, but those toxic mushrooms cost him his job. Being toxic could cost you your game, your chat availability and even your account. If you see me in a game, it'll probably be the last time you have to deal with me. If you're on a severe losing streak, play ARAM or watch anime. That's what I do when I lose 2 in a row. Then I come back and win. Also, just like Teemo shrooms, getting mad at toxicity will only make your enemy stronger. Even if someone intentionally feeds, trolls, or rages, ignoring him/her is the best way to troll that person back. They'll literally spend 20 minutes running it down mid for absolutely nothing. Then you'll stop the intentional feeders and the verbal abuse, in time.