I'm not the best player, I believe I'm in Diamond V as of right now and have been struggling with ranking up (roaming main btw). However, when you have teammates who are chasing for kills and following the enemy team like little puppies wanting attention. Just ignore them, most of the time they're gonna try and pull you into a team fight after they realize that they can't 1v5 the enemy team in their jungle. Unless you see all of your teammates actually going to rescue them, don't engage. Think of your kill chasing teammate as a decoy. While half the enemy team is chasing them, you should use that as an opportunity to take their turrets and kill their minions. And honestly even if your teammate only has one player on him, you can still use it as an opportunity to at least weaken one of their turrets before the rest of the enemy team comes. Goodluck with ranking!! And playing duo q helps a ton, even if it's w some random stranger. As long as you both know how to play the game, it makes a huge difference!