Getting S- With Sone

Good Day Everyone!

I am relatively knew to the game and still learning the nuances of it (such has lane rotation etc) but I've gotten to mastery 5 with Sona . To get to Mastery 6 I am not sure how to get to do well enough to get that rank. In most game (whether win or lose) to not die often and I support my team but it never seems to be enough. So I am just asking for any tips or pointers on how best to maximize my playing?

Also as a side question is ranked play determined by your teams or individual performance?

[sona-playing]