Recently riot released the lvl 6 and 7 so I like everybody else is trying to get an S on my lvl 5 champs and I recently played 
top and went 17-1-8 and I got an A plus. After that game I was wondering how the **** do you get an S?
KDA (slightly), CS, Wards (placed and destroyed), Odjective participation. These things are then compared to other players of the exact same champion/role combination.
Playing 
as the ADC will be harder to get any S ranking because right now he is VERY popular. Where as compared to say 
& 
(just as some examples) might be easier to get S ranks due to their very low popularity right now in certain roles.
21/6/17, 20,4k Gold, 241 Creeps. Objective participation. Pinkwards placed. A+. On Tristana btw. What am I supposed to do? Go Tristana Jungle?
Poppy was easy, because I went support on her but how does the game determine which of the two botlaners is the ADC? Only by the difference of kills and assists? Or items like Relicshield? Botlane is unclear to determine because Riot doesn't give out helping information like that.
