This Guide is written to show you an effective possibility to play Master Yi with a hybrid build.
In my opinion is a hybrid Yi the most flexible and interesting way. It combines his three greatest benefits:

1. poking with high dmg early-game with "Q"
2. movement/attackspeed boost
3. staying on lane and possibility to tank as carry with "W"

Using this build allows you too play Yi with high dmg on solo-top. If you stay defensive it also won´t be a problem to survive early-game against double-top.
It´s recommended to use this build in the case you have more tanky team to balance the missing off-tank usually played on top. Combinations with Vi, Wu-Kong, Cho'Gath, Jarvan are nice presets.
Your main function will be to start solo-pushing everytime the enemy team is bussy with pushing or fighting. As a result of this your team has to stay defensive in these situations.

+ early-game lane control
+ high poke
+ easy farm
+ possible to play 1vs2
+ split-pushing
+ flexible
+ tanky without tank build (heal)

+/- hard pushing

- low escape (flash and ulti)
- no cc
- danger: out-of-mana
- danger: enemy`s stuns
- low use in teamfights

This build leads to low mana. This requires an economic sense while using your abilities. You shouldn`t spam your "Q" and it`s really necessary to have at lest enough mana for your heal.
If you get in trouble with your mana-consumption you may replace "Lich Bane" with "Rod of Ages" or any other Mana-Item.

In connection with your AP-Items early-game you should master "Q" and "W" first, to reach highest effeciency.
Having your "W" in stock theirs no poblem to get focused in small figths.

Double Strike(Passive): Watch your passive! Try have passive ready everytime you use your "Q"

Alpha Strike(Q): Used to poke, to lane-clean and to get close to en enemy

Meditate(W): Allows you to stay on lane and to tank if neccesary. Also you can use it to get out of cooldown reduction in fights.

Wuju Style: AD-Boost. Useful in Fights and especially for tower pushing.

Highlander(R): Movement speed and attack speed boost. Best for hunting escaping enemies, pushing towers and escaping.

At first you should stay on your lane farming. You shouldn`t use skills if not necessary. When you are pushed you can clean your lane fast with your "Q" (Your enemies will hate your for this poke).
Spamming "Q" can become dangerous because you will push very hard and get suspectible for opposite ganks.
While doing this you should always try to hit your enemy too. You can increase the chance for this, when you wait until just 2 or 3 minions are left and the enemy stand close enough.
Don´t ever jump on your enemy directly!
When you get involved in a fight you should provoke your enemy(-ies) to use their stuns/mutes and everything that could stop your heal. After you to go directly all in. Whenever you are close to death you start your heal. This heal allows you to tank up to 3 or 4 enemies (as long they don't stun you).

In late-game you have to watch the minimap and wait for the moment you can push a lane. Now it´s nice to have high movement speed, because you will have to go fast from you lane to another.
Tell your team to delay teamfights to provide you more time. You run on a pushable lane and push as fast as possible the tower. Your ulti is a nice additional attack speed boost to push faster or your possibility to escape when they mention your plan. That`s your decision and depends often on the situation. Yet while mid-game you can push two towers alone in one minute.

Try to avoid 5on5 teamfights because you won`t be very strong in those.