Found out what it takes to get an S+ on Thresh.

Go 5/1/13, Soloing the enemy ADC, Securing 2 kills after you ADC dies Have a bounty Have more gold than the enemy Top, ADC, Support, and Midlane. Have the most assists in the game. Do more damage than the enemy Support, ADC, Close to same damage as enemy Top-laner and Mid-lane. Land about 4+ prediction hooks, including enemy flashes into prediction hooks, a invisible enemy, and enemy support engage. Flay 4+ enemies back during their dashes or boosted movement speed Survive a 3v1 tower dive and leave with 2 kills Help secure 2 dragons. Ignore most of your sightstone [This step is key. Typically while placing 30+ wards in a 25 minute game will get you killed 1-2 times due to the enemy jungler or ganks.] and only use it during immediate threats or to prevent immediate threats. Buy only 1 pink ward and never buy one again. Feel free to CS once the laner has left, that being said it applies to all of the above; [x] Top lane [x] Mid lane [x] Bot lane

Getting an S+ on Thresh is too difficult, I swear, It shouldn't be so hard.