i like the part where you say that sometimes everything works and sometimes it doesnt. its a very simple concept and its called "relativity" made up by a german dude going by the name of albert einstein. hes probably dead by now but back in the days we were good friends.
but that aside, what im trying to say is that everything you do that works and feels good and makes you think "oh yes i did such a good play" actually wasnt you doing a good play, it was you doing a shitty play and it only worked due to your enemies doing an even shittier one. and then the next game you do the exact same play because you are still the same person with the same skill but your opponent is an entirely different one and he might just randomly do the right or one of the not so shitty things against your super shitty thing and thus your super shitty thing now fails.
this is because in everything you do, you make TONS of mistakes. in every lane fight you take and every gank you do and every teamfight you make so many mistakes and take so many risks, its only natural that they backfire. even for very high elo players most of them just do those shitty plays in a better, more coordinated and controled way so that they make it work against worse players. but if you spectate these public master/challenger games, there are always people feeding hard in every game same as in every other elo, because for them STILL applies the same concept of relativity that they dont understand, and if this riven feelds 0:5 then its because of babysit or no ganks or just having a bad game. and if she goes 5:0 shes like just good player and carrying n shit. but she doesnt see the same mistakes she makes in both scenarios equally.
this means, what you should do to become a better player is to very carefully analyze your successfull plays aswell as your unsuccessfull ones (because full of mistakes they are equally) and think: "before all this killing even happened, what information of the map did i have, what information of all involved or possibly to be involved champions do i have (cooldowns, powerlevel, position, etc) and what would the optimal scenario, based on that information, be?"
most likely, the answer to that question wouldnt be to make that play you just made, even if you got a kill. and over time you will start to figure out how to maximize the potential of your information to minimize the risk and also the effort (effort meaning investment of resources) of your plays and begin to only make clean plays that require minimum investment for maximum gain.
sure you could 2on1 dive that 0/1 tanky gnar under his tower by using all your ultimates and summoners, but what benefit exactly does it hold? he will maybe lose 10 minions plus you will get the kill gold. after that, he probably just simply continues to free farm because as things are, maokai cant kill a tanky gnar under his tower alone. so was that really the best investment of resources you could have made, or could you possibly have done something better with it, something with even less risk and even more guaranteed reward and possibly with almost no investment at all?
and if you keep doing that and keep up that learning process, you will very quickly come to understand league in a deeper way and your playstyle will become cleaner and more solid, and solid meaning you will climb faster and with less frustration. it means you will be a better player.
