Maybe focus on yourself rather than your teammates? Try not to rage at them and instead just focus on what you're doing and what you can do to win the game. In my opinion if you literally just focus on yourself, like your csing, itemization, mechanics, objectives (Fb turret). If you just focus on these things i think you can start climbing. Maybe try grinding one champ and if you keep getting fed in normals or ranked with that champ then just continue to grind them. Don't play champs just to counter your opponent because you might end up screwing yourself over because you don't understand the champion.