Hi everyone my name is tortiplouf, I'm a master yi main with almost 500k in NA.
Master yi is the first champion i played in league and since my first penta it became my main until i bought yasuo and became a yasuo main xD
But now i'm back with yi and i wont leave him again
I got back to ranked recently and reached Gold, and trust me it was hard ( maybe because i suck or i'm just unlucky xd ) so i'll try to help you get out of silver like me in this guide.
I also have a youtube channel where i post some yi plays, it's a good way to learn yi.

Pros:
-Has a lot of damage
-Can dodge abilities with Q
-Can reduce damage with W
-Highest base movement speed of all champ ( with pantheon )
-The best cleaner of the game
-Easy to play in lower elo

Cons:
-Hard to master
-Need a decent ping to play him effectively since you need a lot of timing's
-Hard to play in higher elo ( Gold + even if it's not that high xD, it is for me )
-Can be kited pretty easily if you dont have ult
-One miss timed Q or W can change a whole fight
-People on the other team will insult you sometimes ( just don't pay attention to them )

Those are the basic runes for yi nothing special

Fervor is a must for yi since he most of his damage comes from his autos

Some people might say that bloodlust is ok on crit yi, but trust me it's not. You need to get ahead with crit yi early on and the new bloodlust is bad early, fervor is just way better.

You need it if you are playing yi in the jungle xD
It's a safe pick and a must in lane
Since the recent nerf to ghost its not that good anymore
You can take it against someone with alot of burst ( Jungle exemple : Kha'zix / Lane exemple : Zed )
Good for splitpushing or ganking bot lane by behind, take this only if you're an experienced yi player

The best way to win with yi is honestly splitpushing unless their team doesnt have alot of cc, like with full stacked guinsoos you can easily 1v3 if you know how to time alpha and meditate, most of the times people won't respect your damage and go ham on you but i'm not very good at explaining things so if you want to learn how to splitpush perfectly, watch someone like neace

If you want to learn how to meditate auto attack reset ( really important in lane ) Play Video