15% win rate akali main needs advise

every recent game, ive had either the best or second best kda, but i just cant seem to win, i can get so fed every lane i gank is a garenteed kill, but i just cant push well enough, and every time i b back, i get my outer turret taken, what should i do? like i keep losing turrets and i just cant seem to teamfight without dying, the only thing is catch opponents isolated and 1shot them. the best game ive lost so far was a 12/6 game.