LF Plat+ to spectate a few games and tell me what I should be doing differently.

Currently in silver, and can't for the life of me figure out how to carry trolls/0-5-0's/leavers. Is it just mechanics? Should I just be CS'ing better? Am I roaming at the wrong times? Or is it strategical awareness? Do I need to understand objectives better? I feel like I have a good handle on objectives, but I can't seem to coordinate the team to get them. When I want to go for dragon, mid keeps farming cs and top hasn't left lane in 15 minutes. Even if I give a heads up like "Oh, dragon in 90 seconds, we should group for it" I get ignored.

Please, someone come tell me what to do. It's every persons dream. Give me orders, instruct me, teach me your ways, Jedi Master.