as someone whose played nothing but the fish
since they were a silver scrub in season 3, i can tell u u can play watever u want in watever role u want once u get the right mentality.
First off don't play ranked just to watch ur lp go up. You'll rank up eventually no need to hound urself about it.
U should focus on improving ur micro and ur macro play as u climb. Work on ward placement, learn to press tab and watch for item/ lvl changes in ur team and the enemies. Understand when to rotate/ roam as needed. Try to synchronize ur back with ur adc or roam when they back and u don't need/ cant buy anything.
Understan win conditions, what ur role is to the team, and what every other champiuons role/ abilities are in teamfights.
Basically, slowly learn the game and better urself. Cux u can't change people. If your team feeds 5 games in a row, either take a break or buck up and understand u cant take their keybaord and play for them.
And let me assure u...it doesnt get better the higher elo u get. You can only change urself
So mute the jerks, ignore the idiots, and focus on how u can help ur team to a win the best way u can