How to extend your lane win to the other lanes?

I have recently been on a huge losing streak, losing 14 out of 20 games and got demoted from s1 to s3 in 5 days. In half of those games, i won my lane, tried to extend it to the other lanes, but still lost it. I am perfectly aware when i play my lane and game horribly, and after every game i like to analyse: what did i do bad, should i trade there or not, should i gank there or not, why i died there (maybe i could easily avoid that) etc. My question would be how to actually carry when you are winning the lane? What i usually tend to do when i win the lane, is to shove the lane in, to look where their jungle is at, and try to gank bot or top as fast as possible. Or when i dont know where their jungle is at , and i find it risky to gank other lanes, then i just try to deep ward their jungle, so i can keep track of their jungler. Sometimes i just feel that, no matter how hard i try to help other lanes, i just cannot help them, because the enemy is too fed and they manage to kill 3 of us in 2 v 3 situation. Any tips on how to do it propperly, or maybe when to gank, and which lane to priortize when both top and bot are losing?