Hi, I'm a nooby bronze 1, I play Master Yi pretty much and I would like to share my guide.
I'm probably not gonna write more chapters because it could take much more time and I'm alittle busy.
Me in a shellnut/nutshell: (I don't know which one, excuse my english) A noob bronzie playing a game called League Of Legends who thinks his guide actually would be good.

Whenever you gank you don't always want a kill, you could just want the enemy to recall, get hurt so your teammate can pick up the kill or get time to farm while the other laner has died or recalled.
So if the enemy has a snare, stun anything like that it wouldn't be extremely good to use your Q (Alpha Strike) right away when you get into range for it. You want to run into lane (sounds dumb, I know) and try basic attacking the enemy laner, now usually the enemy laner turns around to run away and the enemy laner probably still has the stun, snare or slow so as soon as you see the person turn around or do a little animation instantly use your Q (Alpha Strike) so you'll dodge the stun, snare or whatever it is. Then you just have to damage the enemy laner, you could get the kill or just make him/her recall.
However, you do not want to gank if the enemy laner is too close to the tower, tell your laner to bait the enemy laner in or to let the enemy laner push so you get an oppurunity to gank.

So this is how your jungle roots looks like, start off with the krugs, the rock monsters with some help, smite them whenever you want but I prefer smiting right away, unless there are enemies who warded or are fighting, but if there ain't any invaders just smite it right away because sometimes you don't get as much experience as you could of gotten if you'd smite right away so you get to level 2, which is important. After the krugs you head to the red buff, which is the monster with a ball that is red on it's back (incase you're alittle new to League of Legends) don't back off unless you didn't get to level 2, it'll look like you'll die but the stun from krugs are going to help, use Q whenever you can. Go onto the Crimson Raptors (the dinosaurs which used to be the wraiths) and smite if you can. Goto the Wolves, smite if you can and when you're at blue you probably won't have smite, so just fight it out and take the Gromp (used to be the big gray wraith). Now you just take the rift scuttler (whichever is closest to you) and heal with your W (Meditate) before you gank unless you recalled after the rift scuttler.

I didn't make any matchups because it's pretty simple, example: Lee Sin is pretty strong early game so try staying away from him. Another example: Udyr can just stun you with his E (Bear Stance) and just go full in on you with his Q (Tiger Stance) or his R (Phoenix Stance).
Since I'm not doing any matchups I'd like to tell you some other junglers you should avoid.
Lee Sin is really strong early game and weak late game unless he built some defensive stats, so try staying away from Lee Sin early game because if he gets 1-3 kills he could 1v2 or even maybe 1v3, late game you could probably take him down depending on his stats.
Udyr is another strong jungler, don't really know when he's strong but I've been playing quite much against him, enough to know that you should stay away from him unless you're going 2v1 and he isn't fed. So basically, just try avoiding feeding or letting any of your laners feed until late game, if you can do that it's GG. Unless someone trolls... :3

Pros
- High Burst Damage
- Pretty Mobile
- Kinda easy learning to play
- A good ability to get to the ADC in teamfights
- A great ult to chase with
- Strong Mid Game and Late Game
Cons
- No CC (Crowd Control, such as a slow, snare or stun)
- Weak Early Game
- Pretty squishy unless you go a little tanky
- Going in at a wrong situation could be brutal
- A little mana hungry Early Game

(Double Strike - Passive) So Master Yi's Passive is called Double Strike, on every fourth basic attack Master Yi strikes twice, it doesn't do 2 times 1 basic attack damage but it could be pretty useful in a 1v1.

(Alpha Strike - Active Q) Whenever Master Yi uses his Q he teleports across the battlefield with very much speed and becomes untargetable. This spell could critically strike and add-on hit effects works with it and basic attacks could reduce the cooldown of this spell. Master Yi could strike up to 4 enemies while being untargetable, Master Yi ends up teleporting to the champion/creep/monster he used this spell on. A good tip to use this ability is to dodge a projectile with this ability, teleporting to your enemy dealing damage and dodging the projectile, if you don't have good reflexes to dodge it just imagine you were the enemy running away, when would you shoot the projectile? When you think the enemy is shooting the projectile use this spell. You could also avoid damage from like an example, Zed's ultimate spell, they way to do it is to use your Q (Alpha Strike) on someone/something when Zed's ultimate is supposed to detonate.

(Meditate - Active W) Master Yi channels health per second for 4 seconds, this spells healing is increased 1% for every 1% health that is gone, while channeling this ability you take reduced damage and the damage reduction is increased by upgrading this spell. The damage reduction is halved against turrets. A tip when using this is when you're towerdiving and you're low on health you first get out of the tower range and then W to reduce the damage taken by the tower, if you don't get outside of the tower range in time you could take the last tower shot and use your Q (Alpha Strike) on someone/something to get out of the range or if there are minions in range of the tower you could use your Q (Alpha Strike) on an enemy minion so you get untargetable and when your Q (Alpha Strike) ends the tower is going to stop focusing you.

(Wuju Style - Active E) Passive: Grants 10% Attack Damage
Active: Activating Wuju Style gives you bonus true damage on your basic attacks, but the passive is lost while this spell is on cooldown. A tip when using this is to use this against tanks, since they take reduced damage because of their armor you could use your E (Wuju Style) to shred through their armor.

(Highlander - Active R) Master Yi temporarily increases his Movement Speed and Attack Speed and Master Yi becomes immune to all slowing effects. While this spell is active, killing a champion or assisting someone extends Highlander's duration. Highlander's passive reduces the cooldown for his other abilities on kill or assist. A tip when using this is to use this when running away or chasing someone, this spell in a teamfight or a 1v1 could be very strong since it gives you movement speed and attack speed.

Thank you for reading my guide! (If you actually did) Tell me what you think I should change or what you think is bad. Please try it out and tell me what you thought of it!
Thank you for reading my guide, have a good day!
Regards,
Delsoz