How do you carry your team

Think of it less as "carrying" and more as "guiding". I had/have the same problem. Always stupidly ahead in lane, team is feeding, can't figure out how to get them to go where I need them to. Started playing with a challenger support player, and was amazed at how he could easily carry games at plat just through supporting by the calls, pings, and decisions he was making.

Always ping other lanes if you see jungler coming; they aren't always looking at their map.

Type in chat when you are thinking about the next objective, and start pinging for assistance and make sure your team is in a position to help out before you do anything rash.

Keep a positive tone. This is big. Negative attitudes are contagious, and it's easy for a flame war to break out and throw the game down the tubes. Idk how many times I've seen people get caught out of position and throw a game because they were typing some kind of snarky response.

Keep at it. Keep winning over half your games, you will climb, and the people you play with will gradually be more "game intelligent". Don't be the reason your team loses, and you will win more than you lose :)