Some people, take champions on which they have very low training with or first time them in ranked. Now, let me explain this to you : you are the problem. And that is the reason why I, and many, many, many others are losing ranked games. Play champions you know how to play, and not those that you have 10 normal games with because you can't do shit with 10 normal games, you have not even mastered that champ, you don't know animation cancels, you haven't even red any guides i bet... So, the next time you want to choose a champion, pick the one you main or know a lot because you have actual experience and not just experience with bronzies who play normals so they don't have to deal with ranked.
If you disagree, you are garbage. The mentality of taking a champ you don't know shit about in ranked is garbage.
Go to hell if you disagree.
edit : I noticed that in games where my whole team (including me) had mastery lvl 7 on their champs that i have won every single one of those games, this is the proof that you should take mains in ranked and you will improve in your winrate.