If you don't play well, the don't play ranked
There has been a problem lately that I have been seeing in my games, my boyfriend's, and others. Multiple people play ranked but don't play well at all, and end up making the good players on the team angry because they are losing points because they fed. I have lost two ranked games in a row now because 1) multiple people were awful at the roles they played and fed the hell out of their enemy laners, and 2) they would not listen to us telling them to group up and stop feeding or any helpful advice we tried to give them. I just got to Bronze 3 last week, got up to 49 pts, and am down to 0 now because of these kinds of people. I'm trying to advance as far as I can and so is my bf who I duo with before next Wednesday, and we can't when people like this are in ranked.
So if you are one of these people, go back to normals. Learn the in and outs of every role, of the champions you prefer. Learn to counter play against the ones that should beat you and be able to beat them instead. Learn to listen to the jungler or helpful laner, follow up on teamfights, save your ADC at all costs, fight for dragon, ward your lanes and bushes. Don't rage.
If you can play well, try ranked. Stay out of it if you can't, as you well ruin the games for people that actually are trying to win and actually play well.