Become a leader. Be nice and respectful, but hand out guidance to those on your team. If you play ranked LoL you probably understand this concept. In solo-queue LoL, there is a mini psychological battle your team plays every game. Once people start arguing with each other, they tend to lose. Say something along the lines of “Hey team! Lets have one grab our point and the rest go to clocktower and hold it”. If your team communicates better, you have an immediate edge over the competition.
I don’t play ranger so I cannot give you any tips there, but as a thief I can tell you that the AoE damage some rangers put out has been trouble for my team in the past.
Good luck and win some PvP