Summoners can do a lot in a game and it mainly depends on the matchups and how the other person plays I tend to take flash exhaust because whenever I misplay I always like having a final trick up my sleeve or to have a way to take out fed targets. In some matchups like in toplane you're going to lose a lot of the trades and taking tp isn't a bad idea if you get chunked too much or in midlane taking ignite against certain matchups isn't bad. Cleanse can also work to help you easily win certain matchups like against twisted fate if say he's low and he stuns you a cleanse might force him to overextend for the stun and end up in turn suiciding.

I always like to keep my waves under tower for easily csing and when needed against certain matchups you can use a gank because your laner will need to push up for xp and cs but you can also just push it way into their tower if you notice its an ability reliant champion who can't farm well or don't do much attack damage per auto also forcing people to over extend in lane can give you an easy lead by gaining a kill.

Be looking to split push and shove waves 24/7 and my friends love to joke around with me cause I always get high cs counts but it's because I'm constantly moving around the map applying pressure and when you're such a fed Yasuo that no one can 1v1 you they have to send multiple people after you and your team can get objectives easily. Counter jungling in late game is very useful, no I'm not just talking taking jungle camps I mean applying pressure, forcing people out of areas, warding, and stealing buffs and objectives can easily allow for you to continue to pressure a lead. Also when in late game if you have an IE you can easily clear waves and it allows you to constantly split push and apply heavy pressure everywhere.