How do i get an S??

If you're playing a champion who has a sizable or skilled player base you have to play at your absolute best. You either need to make no mistakes or be lucky enough to have your mistakes go unpunished.

You need great CS, great warding, great kill participation with low deaths (kills or assists), and a low match time (showing that you know how to close out a game).

That game in particular was just a stomp. Because you never got to team fight your kill participation was a little under 50%, which is only decent relative to a more typical game. Your CS was also a bit low for a 22 minute match. If either had been better you would likely have had an S.

Very low CS. Especially for champion like Talon. There is no reason why u shouldnt have 150+ on talon in 23 mins. Especially against champion with such weak laning phase like Akali. Also 8 wards in 23 mins is a bit low.