How do I win games?

Basically, to put things shorter, I need help winning the game cuz right now I am at a loss for what to do. I think im not too bad a player and should be winning far more games than I am. Yet i dont. I know ppl are probably thinking, oh here comes another,I'm so good but my teammates suck guy. Well i can tell you that that is definitely not the case here. I've been told that a lot of these "im so pro guys" actually have rly bad match histories which they simply refuse to look at, so before you judge me u should go look at my match history and hopefully you see that im not just some pompous delusional idiot like some other people. I can honestly only think of three times when i was the one feeding and that was three irelia games cuz im just trying to learn her. But other than that i tend to do pretty well in kills, assists, turrets taken, and a lot of the time if im a damage dealer, damage dealt. I also roam a lot and in a lot of cases tend to help the team into late game. but one way or the other, we lose. For any number of random reasons. It could either be, like it is most of the time, someone or multiple ppl keep getting caught. The enemy team is just waaay too fed. Im sure since you looked in my match history, if u were looking at my teammates u might have seen a couple of guys with scores like 2/10 or sth of that nature. I know what ur about to say.Why dont you go gank that lane? If u are saying that then you, my good sir have definitely never played in bronze. I know from experience that going to try and gank these lanes, that literally fed 4 kills b4 they hit six, will only get you killled as well. Even though you urself are fed, its probably not nearly enough that you can be stronger than the four fed guys on their team. So my question is this. After you've pwned your lane, gotten your turret, gotten other lanes turetts, helped out the lanes that are salvageable or even sometimes good. After you've done all this, what then? How do you stop that guy from getting caught. How do you stop your team from making that suicidal baron call when the enemy team are all alive, u can clearly see a blue trinket in the pit and then its only you left to defend your base against the baroned enemy team. How do you get your team to stop fighting them when you're all clearly behind and the only option is for the fed assasin (me) to splitpush and draw more than one guy to him. Honestly i would like to say that its starting to look like in bronze its just plain luck. I have korean friends in NA plat and diamond who have told me I should be in Gold. It kinda makes sense cuz when I play with them in norms (on smurf accounts admittedly) I dont feel out of my league against the gold and high silver opponents I face, and this is considering that I play from Thailand,with 285 ping on a good day. I know people are going to be all boo hoo hoo. How come high elo players can easily carry out of low elo. Well is that it? do you have to be challenger to get out of bronze. U cant be silver or gold and get to silver or gold you have to be challenger? No i recon that makes no sense. So there must be something probably pretty trivial that i'm missing. I would like to hear your honest opinions if you can think of something i should be doing better cuz right now I have to say, the frustration levels are unbearable.