Master Yi is a champion with an amazing late game. Although his early games aren't great, he can easily snowball with some farm and kills.

Pro's Can Murder any squishy in Seconds One of the best Splitpushers/Backdoorers Snowballs easily Very Rewarding Champion to play

Con's Squishy Focused alot Thornmail may ruin your day Needs farm to be usefull Early game isn't good People may call you a Yi Noob

Core Items

Your boots. You need the movement speed to catch your prey.
Plenty of life steal and attack damage
or More crit chance and movement speed
This item is a must have item for all AD champions who crit. The 250% crit damage will make your auto attacks murder people in seconds

Optional

Get this item if your getting cc'ed alot
If you want more crit and attack speed
Guardian's Angel If you're getting focused alot and you want a second life
Just cause your mean and you don't want anyone escaping
You want more AD and life steal

Start of with Alpha Strike because its your main harass skill. Then at level 2, I like to get Wuju Style because the extra ad helps with last hitting even more, and a stronger q. I get an early 2 points in Meditate because its a good skill for sustain. Obviously a point in Highlander at levels 6, 11 , and 18.

This is one of the best Summoner Spells in the game. You can escape through walls or flash closer to your running enemy.

Another one of my favorite Summoner Spells. Ignite can be used to finish of champions or to counter ultimates like Cannibalism and Maximum Dosage

Replace Ignite with Smite if you're jungling

Others

You can get a huge boost of movement speed, but you have Highlander so it's not really needed. Flash is better because Master Yi doesn't have a built in skill that allows you to escape through walls.

Slows down the target. This spell isn't bad as it can lower the damage output of ADC's dramatically.

Pro's Can Murder any squishy in Seconds One of the best Splitpushers/Backdoorers Snowballs easily Very Rewarding Champion to play

Con's Squishy Focused alot Thornmail may ruin your day Needs farm to be usefull Early game isn't good People may call you a Yi Noob

Early Game

Just last hit the minions and avoid pushing your lane.At level 3, your Alpha Strike should do some decent damage, so try to harass your opponents by using it on a minion.

Mid Game - late game

Just find a squishy target. Pop Highlander, Wuju Style, and Alpha Strike. Then auto attack them to death. Rinse and repeat

In team fights, after your tank initiates, just jump on the adc, and/or apc. Then they lose their damage dealers and the team fight is as good as won