Im YICARY! i reached dia3 with a 75% winrate last split with Yi and diamond 1 with a 65% winrate. This Season is rly good for Yi and my goal is to climb even higher!
I just love playing Yi and sometimes i even stream it :)

Fullclear from top to botside or other way round.
depending on where ur strong side is, u wil ltake the early objectives. if ur botlane is winning, u take first drag and give voidgrubs. if ur top lane has prio, u take early voidgrubs. if all ur lanes are winning, try and take both.
normally u will take drag at lvl 5 after ur first 2 fullclears. its not necessary to gank a yi early, since u want to get ur ult as quickly as possbile. only gank early, if its an 80% play. so basically, its always an kill or atleast a flash.
after getting the first objective and hitting lvl 6 u will keep on clearing ur camps and only gank if u rly need to or u tracked the enemy jungler well, so u know when to countergank.
after early game its hard to say, how to exactly path. it depends on ur team winning or losing. if u have a lot of vision and a romaing support, u wann invade more and put wards into enemy jungle. if ur team is losing, u wanna secure atleast all the jungle camps u can in ur own jungle and try to clear vision and ward baron/drag.

for jungle camps clear: always aa first, then q. use ur w as an aa-reset or as a heal if ur low. w has a low cd nowadays, so dont worry about using it for higher clearspeed.
activate ur e NOT instantly and always DURING the aa-animation or q animation. it will still procc the damage and u have it a little bit longer.

for fighting: stack ur passive to be rdy if u wanna fight (ideally). if not mostly in early game,u wanna hold ur e for the first 3 auto attacks and then surprise him with ur damage -> double aa with ur e into insta w-reset aa again. most ppl wont expect ur damage and try to flash away-> and then u can just follo with ur q.

titanic hydra combo-> if ur passive is ready u can instantly stack ur passive again. well, u probaly already that u need to aa three times to get ur passive ready as yi. so if u a passive double aa with yi,u will already have ur FIRST STack. then u will instantly afterwards do a w-reset aa (ur SECOND STACK, and then instanly press the active of titanic hydra, since this also aa-rest (ur THIRD stack). Et voila, ur passive is rdy again for doing a double aa. if u do it cleanly , u will do 6 AAS in one combo.

U can buy the "blue print Jungle Guide" Book on amazon. its pretty cheap and old, but makes u understand of some key mechanics of the game and how the game should actually be played. i hghly recommend it. i also watch some high elo yi mains like:
Theo
https://www.leagueofgraphs.com/summoner/na/T%C3%A8o-May13
or Sinerias
https://www.leagueofgraphs.com/summoner/euw/Sinerias-EUW
i also can highly recommend to check out both of those guys to improve on ur yi builds and playstyle.

TY FOR READING THIS GUIDE! <3