I cant win ranked

Every Time I play ranked I get dominiated and I try my hardest and it makes me not want to play anymore since i just get destroyed so hard my team says im feeding on purpose and to go kill myself aka toxic behavior. And I do well in regular but i just get dominated and people that i know that play say just keep playing ranked and you will get better but I dont. I watch lcs to see what I can do to get better. I watch other people play the champs I play and nothing works I get curb stomped every game unless someone goes afk or feeds on purpose and its the worst. What can I do