So I'm originally a diamond level random Starcraft II player (hence my name Randomonium.) Very few people were able to play Starcraft II at such a high level playing random races every game. My secret was that I studied pro games all the time, adapted pro builds and techniques to my style, and then watched every game I played (because Starcraft II has a build in replay system) and identified what mistakes I made. This extra effort allowed me to stay in diamond season after season even though I was playing random and I didn't have god-like mechanics.
Anyway, when I made the shift to League of Legends I got placed in Bronze I. Needless to say I was a little pissed so I just decided to grind games until I at least hit Silver. It seemed like every game I got a troll or a rager or an afk. Every game when it ended I would look at my score and say "I did the best on the team, if only my teammates were better I'd win more games." My loses started racking up and I kept getting demoted. Over the course of several weeks I dropped from Bronze I to Bronze IV and was on the verge of getting demoted to Bronze V.
It was then that I stepped back and had a eureka moment. All the things that had made me successful in Starcraft II I wasn't doing in League of Legends. I wasn't watching pro games, I wasn't studying build orders, and I wasn't reviewing my games. If I wasn't willing to put in the same effort then why was I expecting the same result? I realized that I DESERVED TO BE EXACTLY WHERE I WAS.
Since then, I watch pretty much every single NA and EU LCS game. I pay attention to how the pros get advantages, how they rotate to take objectives, how they ward, and how they come back when they are behind. I also have downloaded replay program for league (SkinSpotlights Replay) since for some reason even after 5 years Riot still doesn't have a replay system in their game. I watch every game I play and look for mistakes** I made**, NOT MISTAKES MY TEAMMATES MADE. The final piece of the puzzle is I only play ranked games when I have a duo partner I trust.
Once I made these changes I saw an immediate increase in my win percentage. Since then my KDA has doubled from 2 to 4, I've been averaging around a 65% win rate and I am now at 97LP in Bronze III (from 0LP in Bronze IV.)
My team was so impressed with my improvement that they made me team captain and shot caller and asked me to start streaming our team games and applying my same principles to our team games. We have also seen a huge improvement in our team play and my videos have definitely had a positive influence on them.
https://www.youtube.com/channel/UC2EZm50wNGmfJal7IHM_b8Q