Good morning my friend. I'll offer what I can. Bare in mind I've only peaked in gold, and I don't under any circumstances consider myself a good player.
I think it's critical to know that we are all pretty garbage at this game. Until high plat, most people have no clue what they are doing in the game. For this reason, it's probably unwise to trust your teammates to do anything. Your personal gameplay is more important.
For that reason, I suggest limiting your champion pool to 2 in each role. Read guides, watch videos, practice and try your best to learn these champions. You could also look into a tier list to show you the best champions in each role for each patch. Id suggest nerfplz.com
Once you get to this point, only play those champions. Learn to last hit and try your best to get as much farm as possible. Trading in lane rarely happens in low elo, so instead of worrying about it, just farm. Reach your power spikes then split push.
Every game is different, obviously. Base on your champions you may want to teamfight for often. For example, I play jax and amumu in the jungle primarily. So with jax I try to get strong with good ganks and win the split push game. As amumu I try to get fed with ganks and proceed to group up for team fights.
Keep working at improving your own gameplay. Climbing in league isn't easy but it's definitely possible. I started at bronze 5 when I began ranked and then grew to gold. It just sucks that every new season I get placed in silver again lol.