In general, you gain rating when your team wins a rated game and lose rating when your team loses a rated game. Your individual score and contribution to the game are not really factors beyond how they impact whether your team wins or loses. If you want to gain rating, I suggest focusing on doing your best to improve at the game and helping your team to win in rated games you play. You can find some helpful resources here.
PS: Some people think that they keep losing games because of their teammates but fail to realize their own mistakes. Playing 1v1 games can be useful for learning and can help to provide clarity on skill level in the absence of teammates.