The main problem in low elo is that people always have someone to blame for their loss, rather than looking at their self. Believe me, the key to success in low elo is to start focusing on your self. That means you need to understand that league is a team based game, you win in team or either you lose in team. And it's up to you to show the best of yourself and try to carry games were you are disadvantaged.
There will be games were you can't do anything, you also need to learn to lose. You need to start accept that sometimes the opposite team was better. The thing is, you can learn out of every game. See it like this: Winning is obviously the way to go, but you will learn more by losing . Every lose is an opportunity to improve your mistakes, start reflecting on your games. Not on your team, but on you as a person. Ask yourself these questions: What could I have done better? Did I lose my cool? Did I try to help my teammates rather than blaming them? Maybe I should have farmed more? etc. -> Learn improve and overcome!
Once you understand you need to** work on yourself rather than waste your time on blaming/flaming teammates** you will climb fast as hell. Of course there will always be games were you deserved to win and in which your team are in fact a bunch of bonobos, but guess what? It's part of the game, you will always have bad teams. Sometimes they are carry-able, sometime they aren't. But with blaming and flaming your "mates", you will learn nothing. Even worse , you will end up tilting yourself and your teammates even more, making your chances to win pretty non existent.
I know that sometimes it's hard to keep your head cool, and you want to insult the shit out of somebody. But believe me it's just not worth it. Just leave them be and only use the chat to make calls or giving them a SINCERE "good job". Just giving a simple "Gj" or "wp" to someone who is really struggling in your team rather than flaming them, can do wonders. You will end up boosting their confidence and mood and eventually they will start to play actually good.
And why I'm I telling you all of this? I was one hell of a toxic guy before. I used to blame my team for everything in game and post game. I never tried to see my own mistakes, cause I was too busy blaming/flaming my teammates. As soon as I started working on myself and improving myself to become a better player ( skill wise ) and a better person ( towards other players ) , I started climbing as hell. Just try to give the best of yourself, be friendly,** learn from your mistakes and losses **and you will see yourself improve.
Hope this is useful, good luck !