Let me tell you a story of my trip from bronze to gold. First I was playing fizz in bronze 3, would go 20+ kills and less than 5 deaths. Would lose, would blame my team, which yes it was quite a bit their fault. After a while I realized I'm taking all of the kills, if I can't solo carry then I need to let teammates have some so they aren't completely useless. So your 20 kills doesn't mean shit and awesome kda if your team has 0 between the other 4 of them, they're useless and once you die nothing happens.
Secondly, look at yourself not them. Don't have the mentality "I'm super good my team just sucks" that may actually be the case, but work on getting better enough to where you can carry. An example is I'm sitting silver 4 right now. Had really bad placements due to me quitting and hopping back into ranked. However bronze was still literally faceroll, I've won two 4v5s.
Third change your attitude. Don't consider yourself better than them until you escape them. Attitude can make or break your play. If you're not gold, don't consider yourself gold skilled same with anything above. If you put yourself down on their level, you'll get a lot better because 80% of your teammates and enemies think they're easily plat skill, while in bronze. Trust me this is incredibly hard for me, sometimes I get annoyed, sometimes I get toxic (Usually when provoked by another toxic player)
If all that fails, play heimerdinger top, setup turrets before minions spawn. Max Q, when you get ganked Ult Q run in and out of bush. Hit gold.